ORDES
        PENNSYLVANIA BASELINE
     Par1: 2 -  Impact .-asessment Data Base
 Chapter 1 - Characteristics and Human licMizaticr
        Of Natural Ecosystems
      Section 5 - Surface -ivdrology
            PHASE II
OHIO RIVER DASIN ENERGY STUDY

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                                            June,  !573
               PENNSYLVANIA 3ASEL1ME

       Part 2  -  Impact Assessment Data Base

Chapter 1  - Characteristics and Human Uti!izatior

               Of Natural Ecosystems

          Section S ~  Surface Hydrolocy
                       3y
                 George ?. Kay
                Att i1 a A. Sooky
               Maurice A. Shapiro

            University of Pittsburgh
         Pittsburgh, Pennsylvania  152&I


                 Prepared for

      Ohio River Sasin Energy Study  (CR3.ES)

          Gran; Number °,S05603-01 -03


     OFFICE OF RESEARCH A;iO OEVELC = M.E:iT
    i.S. EMVIRGNMEMTAL "^CTECTICN AGENCY
           WASHINGTON, D.;. 20^60

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                                 TABLE CF CCiY_±Ii_S
2.1.5-    5UF.FACE HYTROLCC-Y
                       -*,    '"l^KIO'^Q "l  —*-^1*--VVTt-*2~  < ""^0^*10 '"**"" —V^^ -* O "• *• •-*V^ _-•—••-•»—• - ,_ i i _- ._   	— ._ _ — "3
                       —• •   '-* v», .w*. '_»_  . --i.o '« -*- —'—C.—  wi. -C^. C-— « —» — k-C. -* — W*. i                        _,
                       C.   Historical  lescripticn-Channeis 4  Hydraulics	^
                       D.   Historical  7lev;  "/ariaticns	6


           o  •  ^  o   ~_:~  v'~~i_TDT7Tr ~  /~~;''  i\^~  .—•_~T~ c' ;~~:c		- •"
           Z..—.j,Z.   	   	i—Z. .— .'_**_  .-ul-x  	. — .-^JJ_ !•„——"——- ~~———————————_ _,

                       A.   'Tr.s  i'lcriCr.ssjn-sla  River  Basir.	10




                                    3_i_k r*.. y i —'-/suw. ^.•-•Li.y"" -       j    i^-«.. —i-n i ^—^^i - - —^-«————..—_^_
                            JT    .*^V 3 ^- V ^ 1  ~"^^V1Q •^T'^v^'* ^ — ~ -^— _, _,  ,   _•• — m.i—	 •_•	.. • —-_»-i^ •• 	 	" "^






                            3-   Tricurary Strear^s	-21"







                            2_   ^asi'i C" "i""1"' ~^rat"'r*~	

                                 ~-a^_. ~

                                    _/L^ i^ii *»_<^.



                            "l.-j.r-ie.vi^ i  ••» ^^ .. -• — -•


                            2.   '""""".e  -J.1"*^^^1


                            Eictrere  Conc.i"icr.s	



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rizure  ::o.
2.1.5 • —1        Pressn~ ar.c Probable r^elaoial Drainage  Patterns                2
                 of  Western Pennsylvania             .-     .

                 ?/Tan .*~> i^ ".^Q^.^r^c^o'^••0*1 3 ^-?--a-^ ^p 5-' y^                                   T 1

                 Mac cf Allegheny river Easir.                                      20

                 Map of ?A "ER Suc-casi^: =21  'Vccer :r±:  i'lair. Ster}              29

2.1.5--5        Duration Curve  of ?lov:3 for  Sev/ickley, Pennsyiv
•a r •• 2
                 relation ci jiscnarge ac  ^incinna"! oc  .-.veragr  .rave^
                 Tijne  of V:ater  frcr. PitOo'c'-crgh

                 low Flov/ Variability ir. ".--/esvern Penr.sylvar.ia

2.1.5.—B        Mir.irnuri Seven  2ay P.unr.ing Averages of ~l:v/ at
                 Sewickley, Pennsylvania

                  Seve^ Ca"r  "'.'jrjr.iriS!  -ve^ase """" ov.' s.7  Sevrici'ile1."   Pemsvlvania

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Table :'o.                       Title                                           Page


2.1.5--I         Counties cf ~he Mcncngahela  River Basin                        13
                of the Mcnongahela River Basin

2.1.5.-3        Characteristics of the Mcnonsaheia River '.iavi-                 Ic
                gation System

2.1.5.-^        Major Multipurpose and Power  Generation                        13
                Reservoirs in the Xcncngahela River Basin

                Counties of the Allegheny  River Basin                          22

                Physiographic Characteristics of Major Streams                 23
2 . "• . ^ . — "         Characteristics of the  -.llesher-Y River ."a"/i£ra~ion              2o
                 System

2. 1.5. -3         Major Flood Control and Multi-rjrccse Reservoirs               27
                 ij?  t^'^s -* ^ 2_osr'S!^iv ~"'j_"'''<=i"''*  ^P s iLr1

                 Counties of PA DER Suc-casin  =2C (Vorer Chio ana               30
                 Pga*,'evv "'ive^s in ~-!-^

       10        Characteristics o""1 t^e  Vocer  Chio RjL".~er 'yavisaoi^n             3"^
                 System

                 Major Reservoirs cf ~.:e Beiver RJ.ver Basir.                     3-'

                 Hydroiogic Characceri sties  of >'cncngahela Basin Streams        36

                 Rlcv/ DLiration Characteristics of St^earr.s —~. che                ~™
                 Mcnongahela River Basin
                 and Tributaries



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 Table :'o.                         Title                                        Page



 2.1.5.-19        Oreat Floods en Ma.;'or Fivers of Western                  •      49
                 ?emsy 1 varla

 2.1.5.-20        .Allegheny River Discharges for Various Floods                  51

 2.1.3 --21        Mcncngahela River Discharges for Various Floods          '      52

•2.1.5--22        Flood Flows  and Elevations - Allegheny Fiver                  53

 2.1.5--23        Flood 71;ws and Elevations - Mcncngar.ela Fiver         '        5^

 2.1.5.-2^        7-^ay, 13-Year Lov; Flews in the Monongahela                    58
                 River E«.sin

 2.1.5--25        7-^ay, 13-Year Lev; FIov.s ir. the Allegheny Fiver  Basin         59

 2.1.5--25        7-Day, 13-Year Lev; Flews in the Upcer Chio and 3eaver          cO
                 Basins

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2.1.5.  SURFACE HYDROLOGY
2.1.5.1.  HISTORICAL CONSIDERATIONS
A.  Prehistoric Surface Hydrology
     Prior to the first Pleistocene glaciation (Nebraskan), western Pennsylvania
was drained by three northerly flowing rivers which emptied into an extension of
the St. Lawrence River*.  The western-most basin consisted of the Allegheny River
south of Clarion, the Seaver, Monongahela, and Grand Rivers.  The resulting water-
way, often termed the Monongahela-Beaver or Pittsburgh River, emptied into the
St. Lawrence at what is now the shore cf Lake Erie between Ashtabula and Geneva-
on-the-Lake.  The central waterway, the Old Middle Allegheny, consisted of the
Allegheny main stem from Emlenton to Franklin, Conneaut Creek, French Creek, and
Crooked Creek; its direction of flow was northwest between the Ohio line and
modern day Girard (1).   The third preglacial  waterway, the Old Upper Allegheny,
flowed from south of Warren by way of the Chautauqua depression (2, 3, •!).
     The arrival of glaciers in northern Pennsylvania brought ice and glacial
debris which dammed the northward flowing streams and caused them to reverse
their flow.  The most significant break to the south occurred in the vicinity of
New Martinsville, West Virginia.  The divide in this area which formerly contained
the headwaters of the ancestral Ohio River was cut through and the waters of
western Pennsylvania were re-routed to the Mississippi Valley.  Netting (2)
believes that the modern day drainage pattern was establ ished by pre-111 ino'ian
or  Illinoian Glaciation rather than by the V;isconsin as seme writers claim.  It
is  known that during the last interglacial period (Sangamor), a great deepening
occurred in the Upper Ohio valleys.  F'gure 2.1.5.1 illustrates the probable pre-
glacial drainage pattern along with the present system.
     Noecker et al (3)  note "hat these prehistoric changes in basin conformation
 "At this time, the Great Lakes had not yet formed and the St. Lawrence flowed
 along its present day axis.

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                          F I G 0 R  E   2.1.5. - 1






                 PRESEOT AND PROBABLE  PREGLACIAL DRAINAGE


                  .   PATTERNS OF WESTERS PENNSYLVANIA
     tv
                  ,/     i  ,
             ,  **fi^l2F"
             I I <-^
Ya«nq»>o««0 '\    •*    V^^ Clqrton          i
   {	'^S.\N«'"^°"lt
 —. J-.-'-R:::-:* *
  E. L.xrfOool
               ^^'x'lOBIlM-B  '           !
        e. Merimtxiit   ' ' , .    i           i
      """7  ?  &
                                      5- ;ioei3i s.-'.
SOURCES: Noecker st. al. (3); Leverett (4)

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are of great significance in the occurrence and present distribution of the



highly productice alluvial  deposits of the Pittsburgh vicinity.   The afore-



mentioned changes are largely responsible for the presence of valley fill  materials



in the Allegheny and Ohio River valleys which are conducive to the development of



large ground water supplies.



B.  General Historical Characteristics



     The aesthetic appeal of a waterway, although difficult to qualify and imposs-



ible to quantify, is inextricably linked to nydrologic variables.  Basic physical



characteristics such as stream velocity, flow, meander pattern,  gradient,  and



overall basin morphology enter into man's appraisal  of beauty perhaps even more



than the chemical quality and biological diversity of flowing waters.  The earl-



iest descriptions of the Upper Ohio consist chiefly  of aesthetic appraisals.



     The Frenchman LaSalle is credited /nth having been the first European to



discover the Ohio River (circa 1670).  The French, who considered the Allegheny



and Ohio to be the same river, named the waterway "La Belle Riviere," or the



beautiful river.  Much controversy surrounds the origin of this  name.  American



Indians  referred to the river as "Oyo" a word which the French  thought was derived



from the Iroquois word "oyoneri," meaning beautiful.  However, John Hec':ewelder,



a Moravian missionary of the eighteen century, later theorized that the French



had erred in their translation and that "Qyo" was actually a form of "Qhiopeekhanne,"



the Miami Indian word for "white fcamir.g river" (5).  Heckewelder noted that:



southwesterly winds were capable of producing "white caps" severe enough to pre-



vent canoe travel.  References to the wind occur in  other historical pieces of



literature.  Douglas Soutnali Freeman, a biographer of George '-iashingtor:,   described



Pittsburgh as "the windswept uninhabited point of land where the turbulent Allegheny
                                                \                               "


received the waters of the slow, powerful and silent Monongahela..." (5}.;-



     Regardless of the etymology of the rivers' name, the waterways of western



Pennsylvania were indeed appealing in pre-settlement and settlement times.

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Celeron de Bienville, a chevalier commanding a military detachment in 1749, was

the first European to sail on the Ohio.  He described the area in the vicinity

of the modern day "Point" as being the fairest spot along La Belle Riviere.

George Washington was also enthralled with the waterways  in this area ,although

chiefly from a strategic perspective (5..

     Perhaps the most romantic description of the Ohio Basin can be found in the

writings of the famous naturalist, John James Audubon, who made a float trip

from Pittsburgh to Louisville in 1803.  Twenty years later, Audubon reflected on

his excursion and the changes occurring in the river valley since that time (5).

               Nature, in her varied arrangements, seems to have felt
          a partiality towards this oortion of our country.  As the
          traveler ascends or descends the Ohio he cannot help re-
          marking that, alternately, nearly the whole length of the
          river on one side is bounded by lofty hills and a rolling
          surface; while on the other extensive plains of the richest
          alluvial land are seen as far as the eye can command the
          view.  Islands of varied size and form rise here and there
          from the bosom of the water, and the winding course of the
          stream frequently brings you to places where the idea of
          being on a river of great length changes to that of floating
          on a lake of moderate extent...Purer pleasures I have never
          felt; nor have you, reader...

               When I think of these tires, and call back to my mind,
          the grandeur and beauty of these almost uninhabited shores;
          when I picture to myself the cense and lofty summits of the
          forest, that everywhere spread along the hills and over-
          hung the margins of the stream...When I reflect that all
          this...is now more or less covered with villages, farms,
          and towns...that steamboats are gliding to and fro over the
          whole length of the majestick river, forcing commerce to take
          root and to prosper at every spot...when I see the surplus
          population of Europe coming to assist...and transplanting
          civilization into its dark recesses...when I remember that
          these extraordinary changes have all taken place in a short
          period of twenty years I pause, I wonder, and although I
          know all to be the fact can scarcely believe its reality.

C.  Historical Description - Channels and Hydraulics

     Prior to the undertaking of slackwater navigation improvements by tne U.S.

Army Corps of Engineers, the Allegheny, Monorgahela, and Ohio Rivers were known

to have harbored numerous physical impediments to water based transportation.

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Wiley (7) notes that numerous snags (i.e. fallen trees and boulders), in addition

to many shallow areas resulting from sandbar or shoal formation, constituted

major hazards to early navigation.  In his classic work, The Navigator, riverman

Zadock Cramer (8) emphasized the need to remove the abundant "rocks and ripples"

in the reach of the Ohio River between Dittsburgh and Mingo Town (downstream of
                                                            ., >,*# *: ?:'-:  *•'
modern day Steubenville).                                    "    '  ''•'••"''
                                                                      r*  "
     Along each of the "Three Rivers," depth and current velocity varied sub-

stantially.  References indicate that the rivers consisted of alternating reaches

of sluggish, deep pools and extremely shallow riffles or rapids with powerful

currents (9, 10).  The crews of early cargo boats employed long poles to move

upstream in the deep reaches; however, crude winching techniques were often

required to perform the same task in fast, shallow water.  Historical evidence

also suggests that all three rivers could be waded during normal flows, especially

at areas downstream of major tributaries, where natural deltas formed at the

mouth of tributary streams.

     The Corps of Engineers  (9, 10) describe the physical characteristics of the

Allegheny and iMonongahela Rivers prior to channelization as follows:

               One of the earliest, if not the first, recorded survey
          of the Allegheny Rivers was performed by Lieutenants C. Graham
          and J.M. Berrien (1328)(11).  At that time, river widths
          varied from a maximum of about 1,200 feet towards the mouth,
          to an average of about 1,050 feet in the vicinity of the
          Kiskiminetas River, and eventually to about 550 to 900 feet
          towards the upstream limit of the present slackwater naviga-
          tion improvements.  Islands were present at normal intervals
          of 3 to 5 miles throughout mcst of the reach.  Riffles and
          sandbars or shoals were not shown on the survey, but pre-
          sumably they existed.  The meander pattern was relatively
          gentle in the lower portion of the reach, becoming more pro-
          nounced in the upstream portion as is in evidence yet today,

               The first recorded survey of the Monongahela River was
          performed in 1333 under the cirection of Dr. '/Jilliam Howard,
          U.S. Civil Engineer (12).  At that time, the river rapidly
          narrowed in width from about 1,300 feet near the mouth to
          about 600 feet near the mouth of the Youghiogheny River
          (r.m.* 15.5).  Between the nxuth of the Ycuchiogheny River
*r .rn. - river mi 1 e .

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ey's
the
          and the upstream limit of the survey at Brownsville (r.m.  55)
          the river varied between 300 and 600 feet in width.  Numerous
          ripples, shoals and bars were noted at intervals averaging
          slightly over 2 miles, but commonly varying in spacing from
          over 3 to less than 1  mile.   The river survey bears out '/Jil
          contention (7), based  on other historical observations, of me
          Monongahela's almost complete lack of islands compared with the
          upper Ohio and Allegheny Rivers.  The river meander pattern was
          relatively gentle as is in evidence yet today.

     J.K.  Hoskins, sanitary engineer and contributing author to the  well-known

"Study of the Pollution and Natural  Purification of the Ohio River " (13),

rendered the following account of channel  characteristics of the Ohio main stem

in the early twentieth century.

               The Ohio is largely an alluvial stream in a fairly advanced
          stage of channel adjustment, as  is evidenced by the fact that
          the velocities of flow are quite uniform throughout the length
          of the channel, and also by the  fact that the meanders of  the  line
          of flow are gradual and wide-sweeping.  The stiff clay soil has,
          however, brought about an adjustment to high rather than to
          low discharges, resulting in a channel floor that is relatively
          wide and flat...  The  river bed  in the upper reaches consists
          of coarse gravel and boulders, but in passing downstream these
          are gradually replaced by sand and silt deposits.  The channel
          is made up of a series of pools  and riffles, alternating with
          stretches of rather smooth,  uniform grade.  The depth of the
          water in the pools at  low stages ranges from less than 10  feet
          to over 50 feet, while in the riffles, especially in the upper
          part of the river, the depths are ""requently -less than 3 feet
          at low-water stages.

               The slope of the  river, as  measured by the elevation  of
          the water surface, decreases gradually from 11.4 inches per
          mile between Pittsburgh and Wheeling to 3.7 inches per mile
          in the last 70 miles above its mouth...

               From Pittsburgh to Cincinnati, the channel is narrow  and
          comparatively uniform  in width,  ranging from 1,200 feet to
          1,500 feet at low water.

D.  Historical Flow Variation

     The Allegheny, Mononcahela, and up-jer Ohio Rivers are all 'known to  have

exhibited large variation in flow prior to channelization.   River traffic was

often halted due to low flows that persisted for weeks and sometimes months,

typically in the late summer and early -all (7).  During low flow conditions in

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the reach of the Ohio River upstream of Louisville, the worst shoals are known
to have had minimum depths of one foot of water flowing over them.   Even down-
stream of Louisville, such shoals had minimum depths of a mere two  feet.  The
results of these conditions were disastrous to navigation since a minimum depth
of three feet over bad shoals was deemed to be necessary for steamboats and
river craft of cargo size (6).
     Flooding, because of its devastating- impacts upon civilization, has been
especially well  documented for the upoer Ohio River Basin.  The Pittsburgh area
is known to have been traumatized by floods since the beginnings of its settle-
ment.  References to flooding extend back in time to 1756 in letters emanating
from the French occupied Fort Duquesne.  The first recorded crest is from the
January flood of 1762 and records exist for fifteen additional floods before
1385.  Although the cutting of forests snd draining of swamps are believed to have
intensified the flooding problem in recent years, the available historical data
indicates that flooding has always been a problem in this region.  In 1763, before
a single swamp was drained, the Ohio River crested at a modern height equivalent
of 44' feet at "the Point" in Pittsburgh (6).  The downstream results of this
flood prompted the Shawnee Indians to relocate their main village from the mouth
of the Scioto River to Chillicothe, Ohio.
     Throughout the nineteenth century, even the ordinary high waters of late
winter and early spring posed a significant threat to navigation since such flows
often carried swiftly moving ice flows.  Further discussion of the history of
floods is included in Section 2.1.5.3, 3.
E.  Human Modification of the River System
     By an Act of Congress approved on May 24, 1324, the U.S. Army Corps of
Engineers was given the authority to remove the "planters, sawyers, and snags"
from the channel of the Ohio River.  Snagging and clearing operations were also

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carried out on the Monongahela River at this time.   The Allegheny River,  however,
did not receive any extensive attention until  the latter portion of the 19th
century.
     The earliest attempts at improving navigation  consisted of the construction
of stone wingwalls in the rivers.   These structures served to concentrate stream
flow and thereby increase water depth in the rapids.  Later, towards the'm'iddle
of the 19th century (1839-1886), the .Monongahela Navigation Company built Locks
and Dams Nos. 1-7 on the Monongahela River.   These  structures, essentially the
first slackwater locks and dams of the Pittsburgh area, generally provided a
lift of less than ten feet.
     In 1375 a proposal emerged to provide a minimum channel depth of 6 feet in
the Ohio main stem.  The proposed task was tc be accomplished by the construction
of 68 movable dams.  The first of these was  constructed in the fall of 1335 at
Davis Island (r.m. 4.7).  Although this initial  structure only maintained an
upper pool elevation of 703.0 feet above mean sea level (rr.sl), the City of
Pittsburgh is reported to have had ample harbor space even during low flow condi-
tions (6, 13).
     It is a generally accepted fact that the expansion of railroads during-the
latter portion of the nineteenth century had a substantial impact on public
opinion of river based transportation.  People began to view the waterways as an
inefficient and outmoded means of travel.  Consequently, Santa (6) has labeled
the period from 1835-1922 as a time of stagnation in the plans for cnannel izUion
of the Ohio.  Nonetheless, a real  flurry of construction activity occurred in the
Pittsburgh area during the turn of the :entury.   Between 137^ and 1903, slackwater
navigation was extended to the head of the Monongahela River by the construction
of Locks and Dams Nos. 3-15; and in 1397, the U.S,  Government acquired Locks and
Dams Nos. 1-7 from the Monongahela Navigation Company.  Between 139
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Lock and Dam No.  1  was constructed on the Allegheny River at mile 1.7.   Construc-
tion of Allegheny L/D Nos.- 2 and 3 followed between 1898 and 1908.   In  addition,
the following locks and dams were constructed on the upper Ohio:   Lock  and Dam
No. 2 (r.m.  9.0)  from 1898-1906; L/D No.  3 (r.m. 10.9)  from 1399-1907;  L/D Mos.
4, 5 and 6 (r.m.  18.6, 23.9 and 28.8 respectively) from 1392-1908;  and  L/D Nos.
7, 8, and 9 (r.m. 36.9, 46.1 and 55.6 respectively) from 1904-1914.
     Throughout the twentieth century various modifications of the  slackwater
navigation system have taken place.  Tha  general trend  has been to  reduce the
number of separata structures, replacing  several at a time with a single larger
structure.  The Emsworth Locks and Dams,  constructed on the Ohio in 1921, replaced
the Davis Island Lock and Dam and Ohio River L/D No. 2.  In 1938, when  Emsworth-
Pool was raised by 7 feet by dam reconstruction.  Allegheny River L/D No. 1
and iMonongahela River L/D No. 1 were al so'el iminated at that time.   In  addition,
the Oashields Locks and Dams replaced Cnio River L/D No. 3 in 1929; the Montgomery
Locks and Dams replaced Ohio River L/D Nos. 4, 5 and 6  in 1936; and the Mew
Cumberland Locks and Dam replaced Ohio 3iver L/D Nos. 7, 8, and 9 in 1960.
     Various Allegheny and iMonongahela structures were  reconstructed and/or moved.
Among these were the Monongahela L/D Nos. 2 and 3, built at new locations in 1934
and Allegheny L/D Nos. 2-6  (Nos. 2-5 were moved to new  sites.)  The original
Allegheny L/D Mos.  7, 8 and 9 were replaced by new L/D  Mos. 7 and 3 at new sites
in 1925.
     The series of locks and dams in use  (see Tables 2.1.5.-3, 2.1.5.-7, and
2.1.5.-10) have significantly altered the channel and hydraulic characteristics
of each river.  The effect of these structures has been to create almost constant
river stages within each pool in spite of wide range of river flows.  Slight
increases in river widths and substantial increases in  river depths have resulted
from empooling large reaches.  The -degree of water level fluctuation within a

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navigation pool is largely the result of the type of dam utilized.-  Gated dams,
which predominate in the Monongahela and Upper Ohio, maintain relatively stable
pool elevations whereas fixed crest dams pernit water level fluctuation.
     Each of the "Three Rivers" are dredged as necessary in order to maintain
the navigable channel at a minimum dept.n of 9 feet.  The Corps of Engineers
contracts the majority of this work to orivate companies.

2.1.5.2.  THE  "THREE RIVERS AND THEIR BASINS
A.  The Monongahela River Basin
1.  General Description
     The Monongahela River, or "Mon'1 as it  is colloquially known, is formed by  the
confluence of  the West Fork River and T/gart Valley River at Fairmont,  West Virginia,
From its s.ource, the Monongahela flows ~'n a northerly direction of 123.7 miles  to
Pittsburgh, Pennsylvania where it meets the Allegheny to forrr the Ohio.  Although
71* or 91.6 miles of the Monongahela's :otal length is contained within Pennsylvania,
only 37" of the 7,384 square mile drainage area lies within the geographic confines
of the state.  West Virginia is home to the majority of the basin (4,223 so. mi.),
while Maryland accounts for a mere 420 square miles of drainage area.   Figure
2.1.5.-2 maps  the geography of the tota" basin.
2.  Basin Configuration
     Hydrologically, the Monongahela Basin  is bordered by the Ohio River main
stem drainage  to the west, by the Little Kanawha and Kanawha River drainage to  the
south, by the Potomac River drainage to the east, and by the Allegheny  R:ver drain-
age to the north.  The entire Monongahe'a Basin is approximately 130 mi"!es long
(north to south) and 75 miles wide (east to west).
     Geopolitically, the Monongahela Basin within Pennsylvania (Pa.  DER Sub-basin
=19) is triangular in shape and contains the following ORBES counties:  all of

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             .-^£y-x>^liv^  :
                                   WESTMORELAND  .
     WASHfNOT. 0  N
        j
          «   E   E
ro F  A  Y  E  T  T  £ /



   PENNSYLVANIA'
                                                /  s
                                                     0 M  E  R .S  E T
                                                             V-
                                                MARYLAND /     /
                   . fumanttta "J^—-
                                              FIGURE  2.1.5,  -  2

                                           P!TTSau«6H DISTRICT, CORPS OF ENGINEERS
                                                PITTSBURGH, PENNSYLVANIA

                                            MONONGAHELA RIVER

                                                     BASIN
                         POCAHONTAJ
                                                     ICill IN «llll


                                                     JUNE 1975
                                                                              _J 'A  , i -J ~i « S
                                                                            ,— ..-.. ^ . U-i-0
                                                                              REGIC^i
                                                                              BOD1C.ARY
  SOURCE:  U.S.  Army  Corps of Enginears (10).

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Fayet'te; most of Greene, Washington, Westmoreland, and Somerset; and a small
portion of Allegheny.  In West Virginia, the basin includes all  of Marion,
Mongalia, Barbour, Harrison, Taylor, and Tucker counties; most of Preston,
Randolph, Upshur and Lewis counties; and a small  sector of northern Pocahontas
County.  The basin in Maryland is limited to more than half of Garrett County.
Table 2.1.5.-1 presents the percentage of land in each county that is contained
within the total Monongahela Sasin.
3.  Tributary Streams
     Fifty-seven tributary streams enter the Monongahela River in Pennsylvania.
The Youghiogheny River, Cheat River, and Ten Mile Creek are the largest and most
hydrologically significant of these streams.  The Youghiogheny drains a 1,763
square mile basin, 72% of which is contained in Pennsylvania.  The upper portion
of the "Yough" Basin lies in western Maryland and a small corner of eastern
West Virginia.  The Cheat River enters the Monongahela River at Point Marion,
Pa., near the Mason-Dixon Line; consequently, less than 7", of its 1,422 square
mile drainage basin is contained within Pennsylvania.   Ten Mile Creek drains 333
square miles, all of which lie in western Pennsylvania.: The physiographic
characteristics of these three tributaries are presented in Table 2.1.5.-2.
4.  Basin Physiography
     The Monongahela River Sasin is situated within the physiographic province
known as the Appalachian Plateau, mostly in the Pittsburgh Plateaus Section, but
partly in the Allegheny Mountains Section*.  The portion of the basin in the
Pittsburgh Section is. characterized by moderate to strong relief.  Erosion has
imparted a slope to almost all of the land.  Consequently, the area is well-drained
and lacks natural lakes and extensive wetlands,  founded hills and ridges reaching
altitudes between 1,200 and 1,250 feet above nean sea level typify the region

*See Fig. 2.1. l.-l  of Geology Baseline

-------
    State
 Pennsylvania
 '••Jest Virainia
*i'!aryland
                    TABLE  2.1.5.  - 1
                       COUNTIES np THE
                     MCNONGAHFU RIVER BASIN
 Countv
Allegheny
Fayette
Greene
Somerset
'•''ash ing ton
Westmoreland
Barhour
Harrison
Lewis
Marion
'lonongahela
Pocahontas
Preston
Randolph
Taylor
Tucker
Upsh'jr
Garrett
Percent of  County
I. and Area in Qasin
       30.7
      100.0
       78.7
                                                              36.8
                                                              42.0
      100.0
       62.5
      100.0
      100.0
        3.6
       99.0
       91.3
      100.0
      inn.n
       33.0
       63.8
   *Mot cart of the QRPF.S Stud-/ Area
    SOURCE: Fed. >'tr. Poll. Cntrl . Admin,  (U)

-------
                                         TABLE 2.1.5.-2

                           PHYSIOGRAPHIC  CHARACTERISTICS OF I1AJOR
                           STREAMS OF  THE  MONONGAIIELA RIVER BASIN
SJj_re_ajii

Mononqahela River

   YouqinoqluMiy River

   Ten Mile Crook

   Cheat River

Tyqart Valley Rivor

West Fork River
Miles Above
Mouth of
Mononqahela
River
0
15.5
65.7
89.1
128.7
128.7
Urainaqe
Area
(sq. mi.)
7,384
1,763
33ft
1 ,422
1,375
880
Length of
Stream
(mi les )
128.7
123
34.1
78
131.8
99
Slope
Average
1.15
17.9
15.7
11.3
19.6
7.5
(Feet per Mi
Headwater
1.6
29.1
-
-
32.6
20.6
le)
Mouth
0.6
1.1
•
-
9.2
0.96
SOURCE:  U.S. Army Corps of Engineers (10).

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between Pittsburgh and Washington, Pa.   Southward and westward of Washington the
topography is steeper with a maximum elevation of 1,600 feet in Greene County.
     The upper Youghiogheny River and its tributaries drain a portion of the
Allegheny Mountains Section in Fayette and Somerset Counties.  This mature upland
plateau of strong relief is home to three anti-clinal ridges (Chestnut Ridge,
Laurel Hill and Negro Mountain) and the highest point in the state, Mt. Davis
(3,213 feet above msl).  The Youghiogheny River cuts through the Laurel Ridge
and produces a spectacular gorge that is over 1,500 feet deep.
     Stream elevations for the entire Monongahela Basin range from 4,842 feet
above msl in the headwaters of the Cheat River to 6 feet above msl at the mouth
of• the Monongahela.  The Monongahela main stem flows through a well defined river
valley with steep sides rising 600-300 reet above the valley floor.  In West
Virginia, the valley width is narrow; however, it gradually widens to about
0.4-0.5 miles in Pennsylvania, downstream of Lock and Dam No. 7.
5.  Channel Characteristics
     The channel thalweg of the Mononganela r^ain stem ranges in depth from approx-
imately 15 to 35 feet  (10).  The shallower portions of the thalweg typically
occur at sites immediately downstream of navigation dams, whereas thalweg depths
of 25-35 feet may be found in areas directly upstream of these structures.  Pool
widths gradually increase  in the downstream direction as follows:
                                             Approximate Pool Width  (Feet)
                                             Normal      Normal      Normal
                                             Maximum     Minimum     Average
          Upper Monongahela                     600       ^CO         SCO
          Lower Moncngahela                   1,000       700         850
Further characterization of specific pools is presented in Table 2.1.5.-3.
6.  Impoundments
     Within the confines of Sub-basin =19, 91 dams impound approximately 275,535

-------
                                               T A II I. E  2.1.5. - 3
                             CHARACTERISTICS OF MONONGAHELA RIVER NAVIGATION SYSTEM
Locks and Dams
Emsworth L/D
(t-'onongahela Arm)
L/0 2
L/0 3
L/0 -1
Maxwell L/D
L/U 7
L/0 U
Morgan town L/l)
Hildebrand L/D
Opokiska L/D
1 . Ohio River mi
2. I'xclur. ive of
River
Mile
6.21
U.2
23.8
41.5
61.2
05.0
90. U
102.0
100.0
ll'j.'l
leage for
West Fork
State
Pa
Pa
Pa
Pa
Pa
Pa
W. Va
W. Va
U. Va
W. Va
ma i ii c
& Tyga
Length
Dam of Pool
Crest (miles)
Gated
Fixed
Fixed
Gated
Gated
Fixed
Ga ted
Gated
Ga ted
Ga ted
1
hannel dam.
rt River Arms
11.2
12.6*
17.7
19.7
23.0
5.0**
11.2
6.0
7.4
13.3***
20.7
of the 0
Upper Pool
Elevation
(msl)
710.
718.
726.
743.
763.
770.
797.
814.
035.
057.

pekisk
0
7
9
5
0
0
0
0
0
0

a Pool.
Surface Area Storage @
Q Normal Pool Normal Pool
(acres) (acre-feet)
1125
1190
1595
1660
1075
420
705
365
405
005
10.145

13,000
14,000
15,000
25,100
31 ,000
5,500
11,500
6,200
7,600
14.4002
144,100

Mean
Pool
Depth
(feet)
12.3
11.8
9.9
15.1
16.5
13.1
16.3
17.0
10. 0
17.9


Commenced
Operation
Sept.
Aug.
May
Aug.
Nov.
Nov.
Oct.
Jul.
Mar.
Aug.


1921
1905
1907
1932
1964
1925
1925
1950
1960
1964


 Inclusive total s.toragc = 17,300 acre-feet.

 Plus an additional 2.1 miles of slackwater on the Youghiogheny River.

 Plus an additional 1.5 miles of slackwater on the Cheat River.

 Plus an additional G.O miles of slackwater on the West Fork and 7.6
 miles on the Tygart River.


Adapted from U.S.  Anny Corps of Ragincura (10,15).

-------
acre-feet of water (16).   Natural  lakes are nonexistent in this region.   In the
Upper iMonongahela Basin,  four large reservoirs (Lake Lynn, Deep Creek Lake,
Tygart Lake and Youghiogheny River Lake'  drain approximately 3,100 square miles
of land.  Deep Creek Lake and Lake Lynn are owned by private power companies and
are operated to produce peak load  power of 51  and 19 megawatts, respectively.
The Youghiogheny River Lake and Tygart River Lake are operated by the Corps of
Engineers for flood control, recreation,  low flow augmentation for water quality,
and navigation.  The four reservoirs contain 720,000 acre-feet of total  storage.
Allocated storage capacities are as follows:  250,000 acre-feet for summer flood
control; 430,000 acre-feet for winter flood control; and 113,000 acre-feet of
usable capacity for power generation.  Table 2.1.5.-4 characterizes the  individual
reservoirs in greater detail.
     The Corps of Engineers' Stonewall Jackson Lake  on the upper V.'est Fork River
is currently (1978) in the "construction  phase"  (real estate procurement).  This
multipurpose reservoir is to be operated  for water supply, low flow augmentation
for water quality maintenance, and flood  control.  The planned gross capacity is
74,650 acre-feet.  The project is  not expected to have a large impact on the
hydrology of the Monongahela Basin due to its small  storage capacity and drainage
area (102 sq. mi.).  The flood control summer and winter minima are projected to
be 26,480 and 38,550 acre-feet respectively.  Approximately 3,120 acre-feet are
planned for permanent storage.  The tentative year of completion for the project
is 1984 (17).
     Planning of the Rowlssburg Reservoir on the Cheat River is new inactive.   The
projected total storage capacity of'this  prccosec reservoir v;as 750,000  acre-feet.
If constructed, it would have a major ^nfluence  on the hydrology of the  region.

-------
                                                               T •  A  B L li   2.1. 5.  -
                                                      MAJOR MULTIPURPOSE  ASD  POWER GENERATION  RESERVOIRS
                                                                 IN  THE MONONCAJIELA R1VKR  UASIN
:, Drainage
*'•' . Date In Area Storage Capacity (1000 ac. ft) Minimum Release (cfs)
Reservoir Purpose Operation Sq. Ml. Minimum Con.sei vat lonc
T.ygaii Valley FNR 1918 1104 9.7 O.OU
River 99. 9S
Youghlogheny VLH 1948 434 5.2 97. BU
149. 3S
Deep Creek P 1925 68.5 11.1
, I...V.C Lynn P 1926 1413 45.0
Fliutd Control0 Power Total Winter Summer Operator
278. OW ~ 2H7.7 100 100 Corps of Engineers
178. IS
151. OW ~ 254.0 100 100 Corps of Engineers
99. 5S
93.0 106.1 _ _ Pennsylvania Elec. Co
19.7 72.1 - - West Penn. I'uUL-r Co.
 1'iojuci  Purposes!  F -  Flood  Control
                   P -  Power
                   H •  Navigation
                   L •  l.ov I'lou  Auf.mcnt.it Ion -
                       P- inclpally  for Quality Control
                   K •  Kcci'uat Ion
t,
 S(or:\£b  Capacity Al locat ions:
 Minlnum  -  Scor.i^c  provided (or  various purposes, ulilch Is not drawn-down nxccpc In unusunl cIrcumatunccs.
 Consorvat Ion  -  Storage vlilcli Is f luctunte>1 as required for  low  flow augmentation, quality control,
                vacur supply,  recreation  and other purposes.
 Power  -  Storage above  llu- minimum  pool which Is drawn down  for  the production of hydroelectric power.
 1'laoJ  Control - Storage r>:feived exclusively for reduction  of floods.
 Total  -  Total storage  In  the  reservoir under a flat pool at ungaced opllluuy crest elevation,
         or  maximum pool elevation  wltli spillway gateu clor.ud.

 W • Winter
 S • Suroer
SOURCE:  U.S.  Ariny Corps of Engineers  (10).

-------
     At the present time, the proposed Davis Lake Pumped Storage Project on the
                                                         *

Blackwater River in the Canaan Valley of West Virginia is under review by the


Corps of Engineers, the FPC, the Ohio River Basin Commission and other environ-


mental agencies.  The proposed impoundment would inundate an area considered by


numerous groups and individuals to  contain unique biota, particularly, wetland


species.  The project would provide 1 ,OCO MW capacity of pumped storage peaking


power; it would impound 162,500 acre-feet of water at an elevation of  3,182


feet above mean sea level.  The resulting 7,000 acre- reservoir would also serve


as a recreational  lake (18).


B.  The Allegheny River Basin


1.  General Description


     The Allegheny River originates outside of the ORBES Study Area in Potter


County near Coudersport, Pennsylvania.  The river flows northwestward from  its


source into .New York State where it bencs, forming a loop 50 miles long before


re-entering Pennsylvania in Warren County.  The river first enters the GRBES


region in northwestern Forest County, from which it meanders in a southerly dir-


ection to its confluence with the Mononcahela at Pittsburgh.  Approximately 5C:l'


of the Allegheny's 325 mile length and 54* of its 11,773 square mile drainage


basin lies within the ORBES Study Area.  The hydrologic boundaries of the entire


Allegheny River Basin are shown in Figure 2.1.5.-3.


2.  Basin Configuration


     The Allegheny River Basin is bordered by the Great Lakes - St. Lawrence River


Basin to the north; by the Susquehanna River Basin to the east; by the Mcnongahela


River Basin to the south; and by the 3e.iver River Basin alone with a segment of


the Ohio main stem drainage to the west.  The maximum diirensions of the entire


Allegheny Basin are approximately 175 miles in length (north-south axis) and 130


miles in width (east-west axis).

-------
                                        1'Iorthem
                                        Boundary of
                                        the ?a. CRBE3
             , . J  ..-v* t «c-.c.  M.C" "    I
            J ,\  f~<^^ ^=\    .}
            C' '•( ,..,<> OTT.....6 ,   .   f.
              S  _/:»<:G. fP c«roV"   j  /^
              v,  •Cu»r  ^.  X  (,'
          / _^f vy <-.:..y^ j^
                              /.
\.
          \.«'  rrfc~  <   /   ' •{-* •'••/')  ^
         „.» .....rlM-rtTW^  /    /     //  f
      .^i^k H«^^AvA^
        i%5S.',Jii-^X ' \ •. O,t-—i CT   .^/ £ ..... ./
        2=«;-3«s'!TTS8 U»SH\ ; s l<  \/^X i;-s?i   ,^
        . I' —*^»'Nv»    \\  \\    S  I \c.  »i*i>"^
           -\V.    t'   v\ 4cr-^  X
                 \   VS.J'*'     / t—-j>    I

                 sv-/-fc^
                    \^/  f    /
                       ../-..-
-------
     Nineteen counties in Pennsylvania and three in iNew York are contained partly,

or entirely within the Allegheny Basin 'see Table 2.1.5.-5).  The Pennsylvania

portion of the watershed covers approximately 9,813 square miles, whereas only

1,965 square miles of the basin occur in New York.

3.  Tributary Streams
                                                                    ,• "'•' ? •  <- -
     Numerous tributaries of various sizes empty their waters info "the'-'AfVedHbny

River along its course.  However, only nine tributary streams exert major influ-

ences on the hydrology of the river.  Most of these tributaries approach the

Allegheny from the east where the topography is rugged.  Table 2.1.5.-6  lists

the physiographic characteristics of the Allegheny River and these major tribu-

taries.  The drainage areas and map coordinates of all streams within the Common-

wealth of Pennsylvania are available in the "Dennsylvania Gazetter of Streams" (19).

Detailed mapping of state streams is available in Higbee's :'Stream /1ap of Pennsyl-

vania" (20).

4.  Basin Physiography

     The Allegheny River Basin has portions of its drainage area in four different

Sections of the Appalachian Plateaus Physiographic Province*  All of Tionesta

Creek, the upper Allegheny and Clarion Rivers, and lower Oil, French and Conewango

Creeks are contained within the Allegheny Hich Plateaus Section, an unglaciated

area characterized by highly dissected plateaus.  Here, stream valleys are deep

and have steeo sides with only small tracts cf flat land on some of the valley

bottoms and stream divides.

     Upper Oil Creek, as well as the majority of the French Creek Basin occurs

within the Glaciated Section of the Appalachian Plateaus.  This area consists of

rounded hills with gentle slopes; valleys typically have broad and flat fiocdpiains,

Several natural lakes and swamps have been formed on the glacial deposits of this



*See Fig. 2.1.1-1    of Geology Baseline

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                           TARLE  2.1.5-5

                         COUNTIES OF THE
                      ALLEGHENY RIVER BASIN
  STATE                  COUNTIES       '       PERCENT  HF  COUNTY  LAMD AREA  IN  RASJN

  Pennsylvania           Allegheny                            31.4
                         Armstrong                           100.0
                         Butler  "                            29.1
                         Cambria                              53.8
                         Clarion                             100.0
                         Clearfield                            9.9
                        *Crawford                             75.9
    "                    Elk                                  67.2   .
  •  "     "             *Erie                                 49.2
                         Forest                              100.0
                         Indiana                              91.9
                         Jefferson                           100.0
                        *McKean                               97.4
                         Mercer                               15.8
                        *P0tter                               28.5
                         Somerset                             37.7
                         Venango                              97.3
                         Warren                       '•      100.0
                         Westmoreland                         58.0

  Mew York              *Allegany                             17.4
                        *Cattaraugus                          74.2
  "    "                *Chautauqua                           71.5
*Not part of the ORPES Study Area

  SOURCE:  Fed.  Wtr.  Poll.   Cntrl.  Admin.  (14)

-------
                                                   T ABLE  2.1.5.  -  6
                                        PHYSIOGRAPHIC  CHARACTERISTICS OF MAJOR
                                        STREAMS OF  THE ALLEGHENY RIVER BASIN
IX)
I .)
Stream

Allegheny River

Kiskiminetas River

Conemaugh River

Malioning Creek

Kecll>arik Creek

Clarion River

French Creek

Oil Creek

Tionestd Creek

Conewango Creek
Miles above
Mouth of
Allegheny
River
0
30.2
-
55.5
64.0
86 . 1
126.6
134.0
154.2
192.0
Drainage
Area
ill:'"' • )
11,700
1 ,890
1 ,370
425
605
1,235
1 ,235
340
480
900
Length of
Stream
_[miles)
325
27
52.2
62.8
47.5
96.3
108 .
45
58
71.5
Slope (Feet per Mile)
Average Headwater Mouth
2.7 33.2 0.9
3.4
6.0
8.0
8.4
6.0
6.5
-
13.1
4.0
            SOUKCfi: U.S. Army Corps of  Engineers  (9).

-------
region.  This is largely because the post-glacial drainage has not yet had the



time required to develop any significant degree of integration.



     Blacklick Creek, most of the Conemaugh River, and the headwaters of Loyalhanna



Creek lie in the Allegheny Mountains Section of the Appalachian Plateaus.  This



is an area of strong relief with a series of high ridges.  The greatest local



relief is approximately 1,500 feet at the Conemaugh River gap through 'Laurel  Hill.



     All  of Mahoning Creek, Crocked Creek and the Kiskiminetas River flow through



the Pittsburgh Plateaus Section of the Appalachian Plateaus.  Most of the Allegheny



main stem, the Clarion River, and Redbark Creek are also contained in this section.



The hill  summits of this section are in general conformity with the local relief.



The maximum relief, between the Allegheny River Valley and the highest hills  is



approximately 775 feet.



     Sasin-wide elevations range from over 2,500 feet above TS! in the eastern



section to 710 feet above msl at the Allegheny's mouth in Pittsburgh.  The



Allegheny main stem flows through a well-defined river valley with a floor width



averaging 0.5 miles in the lower reaches.



5.  Channel Characteristics



     The lower 72 miles of the Allegheny mair: stem are managed for commercial naviga-



tion.  The channel thalweg in this reach, under normal flow, ranges from 10-20



feet directly downstream of dams to 25-30 feet (or somewhat greater) (9).  Channel



widths (exclusive of islands) of the normal slackwater pools range from approxi-



mately 600. feet to 1,500 feet with an average of 1,000 feet.  A more detailed



description of the navigation pools can be found in Table 2.1.5.-7.



6.  Impoundments



     In the Allegheny Basin, a network cf ten large reservoirs are operated  by



the Corps of Engineers chiefly as structural measures for flood control.  These



impoundments have a pronounced effect or, the hydrology of the region as they con-

-------
                                                      TABLE  2.1.5.  - 7
                                               CHARACTCRISTICS OF THE ALLEGHENY
                                                    RIVER NAVIGATION SYSTEM
Locks and Dams
Emsworth L/0
(Al legheny Arm)
L/0 2
L/0 3
l./O 4
L/0 !i
L/0 6
L/0 7
L/0 8
L/0 9
River
Mile
6.21
6.7
14.5
24.2
30.4
36.3
45.7
52.6
62.2
Dam
Crest
Gated
Fixed
fixed
Fixed
Fixed
Fixod
Fixed
Fixed
fixed
Length
of Pool
(mile)
6.7
7.8
9.7
6.2*
5.9
9.4
6.9
9.4
11.0 -
Upper Pool
Elevation
(ft. above msl )
710
721
734
745
75fi
769
782
aoo
822
.0
.0
.5
.0
.0
.0
.1
.0
.0
Surface Area Storage 0
G> Normal Pool Normal Pool
(Acres) (acre-feet)
725
1120
1220
710
660
1260
640
1010
1040
10
14
16
9
9
14
8
15
13
,000
,500
,800
,000
,1100
,000
.400
.200
,500
Mean
Pool
Depth
(feet)
13.8
12.9
13.8
12.7
14. a
11.1
13.1
. 15.0
13.0
Commenced
Operation
Sept.
Oct.
Oct.
Sept.
Oct.
Oct.
Nov.
May
Oct.
1921
1934
1934
1927
1927
192U
1930
1931
193b
 1.   Ohio  River  Mileage  for  main  channel  dam

 *    Plus  an  additional  3.7  miles  of  slackw-itcr on  the Kiskiminetas  River

.SOURCE:   U.S. Army  Corps  of Engineers  (9 ).

-------
trol the runoff from approximately 5,250 square miles of drainage area and provide
a total storage capacity of about 2 million acre-feet.  The allocated storage
capacities for these reservoirs are as follov/s:  625,000 acre-feet for summer
conservation, including low flow augmentation; 680,000 acre-feet for summer flood
control; and 1.7 million acre-feet for winter flood control.   Monthly releases of
water from major reservoirs in the Allegheny Basin as well  as the rest of Pennsyl-
vania are published in the U.S. Geological  Surveys "VJater Resource Data for Pennsyl-
vania" (21).  These reservoirs are characterized in greater detail in Table 2.1.5.-8.
     In addition to publically owned impoundments, several  privately owned reser-
voirs associated with power generation are  situated within  the Allegheny Basin.
The Pennsylvania Electric Company  owns and operates the Piney Reservoir which
drains 957 square miles above mile 13 o~ the Clarion River.  Piney is operated for
hydroelectric power generation (29 MW capacity) and has a maximum summer storage
of approximately 28,900 acre-feet.  The Keystone Station Dam impounds 330 acres
of water on Crooked Creek and north Branch  of Plum Creek in Armstrong County for
use at the jointly owned, 1,640 MW coal-fired facility.  The Kinzua (Seneca) Pump
Storage Reservoir is a 106 acre impoundment in Warren County yielding approximately
246 MW.
     One large natural lake, Lake Chatauqua, drains 189 square miles of Mew York
State.  Although the capacity of this lake  has not been determined, its surface
area is approximately 21 square miles.  Numerous man-made recreational lakes and
several other natural lakes are also distributed throughout the basin.  Among the
more popular of these are Ccnneaut Lake, Lake Somerset, the Quemahoning Reservoir,
Yellow Creek Lake, North Park Lake, the Sear Run Reservoir, Cuba Lake and Edinborc
Lake.  Descriptive material on most of :he  impoundments in  the Commonwealth of
Pennsylvania as of 1970 is available in "Dams, Reservoirs,  and Natural Lakes." (16).
     Several potential sites for Corps of Engineers' reservoirs have been identi-

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                                                         T A 11 1. i:  2.1.5.  - 8
                                          MAJOR FLOOD CONTROL  AND MULTi-PURPOSE RESERVOIRS
RESERVOIR
Al leghcny
(Kiiuua Dam)
ConeiiMiiqh
Crooked Cr.
East Br.
Clarion
Loyalhanna
10
-•i M.iliomng Cr.
1 ionesta
Union City
Woodcock Cr.
-J!
•tf
I
LOCATION v
PA. COUNTY -i
Warren
Indiana
Armstrong
Elk
Westmoreland
Armstrong
Forest
Erie
Crawford
PURPOSE6
FLRP
FR
FR
FI.R
Fit
Fit
FR
FR
FRL
DATE IN
OPERATION
1967
1953
1940
1952
19<.2
1911
1910
1970
1974
in MIL nui
DRAINAGE
AREA
SQ. MI.
2,180
1,351
277
72.4
290
340
473
222
45.7
_HJ|ILI1I IMVCH IJnjIM
STORAfiE CAPACITY (1000 ac. ft}0
MINIMUM
24
4.0
4.5
1.0
2.0
4.5
7.8
0
0.9
CONSERVATION
216. OW
549. OS


44. 6W
64. 3S


1 . 4W
8.4S
0.4W
4. OS .
FLOOD CONTROL ^
940. OW
607.15
270.0
09.4
38. 7W
19. OS
93.3
j9 . /
125.6
46. 3W
39. 3S
18.7W
15. IS
TOTAL
1 ,180.0
274.0
93.9
04.3
95.3
74.2
133.4
47.7
20.0
MINIMUM
w INTER
500
100
5
20
10
10
5
-
5
RELEASE_[cfsl
SUMMER
bOO
100
5
20
10
10
5
-
5
a.  All  owned and operated by Corps  of Engineers

b.  Purposes:  F = Flood Control,    P = Pc.wer
               L = Low Flow Augmentation -  Principally for Quality Control
               R = Recreation
SOU.°.;C:   U.S.  Arny Cor^i  of
                                     ('•> )
Storage Capacity Allocations:
Minimum - Storage provided for various purposes, which  is not
          drawn down except in unusual circumstances
Conservation - Storage which is fluctuated as required  for  low
               flow augmentation , quality control, water supply,
               recreation and othL'r purposes.
Flood Control- Storage reserved exclusively for reduction of  flo
Total - Total storacjv: in the resc-rvoir under a flat pool at
        ungated spillway crest elevation, or maximum pool
        elevation, or maximum pool elevation with spillway
        closed.
                                                                              d.   U = Winter,  S = Summer

-------
fied in the Allegheny River Basin.  The St.  Petersburg Reservoir on the Clarion
River is one of the most significant of these proposed projects.  A storage volume
of 300 thousand acre-feet is the planned capacity at full  pool.
C.  The Upper Ohio River Sub-basin (Pa.)
1.  General Description
     The Ohio River is formed by the confluence of the Allegheny and Monongahela
Rivers at Pittsburgh, Pennsylvania.   At "The Point" in Pittsburgh, the Allegheny
and Monongahela account for 61.5" and 3£.5"  respectively of the Ohio River's
19,164 square mile headwater drainage area.   The Ohio flows southwesterly for 981
miles to Cairo, Illinois where its drainage  area (exclusive of the Tennessee River
Basin) covers approximately 163,000 square miles.  The Ohio Basin in bordered
on the north by the Great Lakes drainage area, on the east by the Appalachian
divide, on the south by the Tennessee Valley, and on the west by the Mississippi
River.
2.  Sub-basin Configuration
     The portion of the Ohio River Basin within the Commonwealth of Pennsylvania
and exclusive of the Allegheny and Monongahela Basins is known as Pa. DER* Sub-
basin =20.  This sub-basin is triangular in  shape with a drainage area of 3,080
square miles.  The base of the "triangle" corresponds to the state boundary line;
it is approximately 139 miles in length (north-south), extending from Pymatuning
Reservoir to Ryerson Station State Park.  The legs of the sub-basin "triangle"
average about 73 miles in length from Pymatuning and Ryerson State Park to Butler,
Pa. (see Figure 2.1.5.-4)
     Geopolitically, Sub-basin =20 contains  all of Beaver and Lawrence Counties,
most of Mercer County, two-thirds of 3u"ler  County, approximately half of Allegheny
and Washington Counties, and small sections  of Crawford, Greene and Venango Counties,
(see Table 2.1.5.-9).

*Penr,syl vania Department cf Environmental Resources

-------
Northern Boundary of
the Pa. OREES Region
                                   rsri
               /JETK-   nsr
FIGURE 2.1.5. - 4

  PENNSYLVANIA DEPT. OF
   ENVIRON. RESOURCES SUE-BASIN
          #20

       (Upper Ohio Main Stem)
    SOURCE: Adaoted frc~ Ohio River Ba^in CcT.nissicn (22).

-------
                          TABLE   2.1.5.  - 9

                           COUNTIES CF PA. DER
                              SUB-BASIN #20
             (Upper Ohio - Beaver Basins within Pennsylvania)

                                                       Percent of County
   State                        County                 Land Area in Basin

Pennsylvania                   Allegheny                    37.9
   "    "                        Beaver                      100.0
   "    »                        Butler                       70.9
   "    "                       *Crawford                     15.0
   "    "                        Greene                       21.3
   11    "                        Lawrence                    100.0
   "    "                        Mercer                       84.2
   "    "                        Venango                       2.2
   "    "                        Washington                   63.2
SOURCE:  Fed. Wtr. Poll. Cntrl. Admin. (14)

-------
3.  Tributary Streams
     Forty miles of the Ohio River extend from Pittsburgh to the Pennsylvania State
line.  Along this reach of the river, 41  tributary streams enter the main stem.
The hydrology of the region, however, is  chiefly governed by only three of these
tributaries - the Beaver River, Chartiers Creek and Raccoon Creek.  These three
streams collectively drain approximately  72% of the land area in Sub-basin =20.
     The Beaver River is the largest and  hydrologically most significant tributary
of the Ohio River in Pennsylvania.  The Beaver is formed by the confluence of the
Mahoning and Shenango Rivers near New Castle, Pa. from which it flows in a southernly
direction for 21 miles before joining tne Ohio at Rochester, Pa. (Ohio River mile
25.4).  The Beaver drains 1,363 square miles of northeastern Ohio and 1,785 square
miles of northwestern Pennsylvania.  The  river's slope ranges from 1.6 feet per
mile at its headwaters to 11.3 feet per mile near its mouth.  The average slope
for the entirety of the river is approximately 4.1 feet per mile (23).
4.  Sub-basin Physiography
     The northern third of Sub-basin =20  lies within the Glaciated Section of the
Appalachian Plateaus.  Rounded hills and  rolling terrain dominate the landscape
in this region.  Most of the major waterways have broad, flat floodplains which
may contain as much as 400 feet of unconsolidated glacial outv/ash deposits (24).
Drainage patterns are generally not fully developed or integrated; consequently,
wetlands are more common in this area than in the rest of the Pennsylvania ORBES
region.  In the past, glaciation overdeepened numerous valleys in this section,
which are today occupied by small, slowly flawing streams.  Crude radial and trellis
drainage patterns are common in this section.
     The hilly terrain of the Pittsburgh  Plateaus Section contains the southern
two-thirds of Sub-basin =20.  In this region, stream valleys have cut into the
upland surface and the drainage system is characterized as being well-developed and
of a dendritic pattern.  In Washington County, hilltops average 1,300 feet above

-------
mean sea level (msl)  with valley floors at 1,000 feet above msl.
5.  Channel Characteristics
     Three locks and dams are located in the Pennsylvania reach  of the Ohio River.
A fourth structure, the New Cumberland Locks and Dam is situated in West Virginia
but has 8.3 miles of its pool within Pennsylvania.   The navigation pools of the
Upper Ohio are characterized in Table 2.1.5.-10.  The river is dredged to provide .
a minimum navigable channel depth of 9 feet.  The mid-channel  depth in actuality,
however, ranges between 20 and 35 feet.  The channel widths (exclusive of islands)
of the first four pools range from 1,340 - 1,400 feet.  The average slope and
thalweg slope of the river in this reach are 0.9 feet per mile and 1.5 feet per
mile, respectively (23, 26).  The average slope for the entire 981 miles of the
Ohio is approximately 0.4 feet per mile.
6.  Impoundments
     The upper Beaver River Basin contains seven large reservoirs, most of which
lie outside Sub-basin ,r20 in northeastern Ohio.  These impoundments collectively
drain 1,524 square miles and have a total usable storage capacity of approximately
713,000 acre-feet.  Table 2.1.5.-11 characterizes the individual  reservoirs in
greater detail.  Sub-basin =20 does not contain any natural lakes but approximately
one hundred water supply and recreational impoundments exist throughout the area.
Lake Arthur is the largest state-owned, man-made lake that is  contained entirely
within the state; it impounds approximately 37,000 acre-feet of water on Muddy
Creek in Butler County.
2.1.5.3.  STREAM FLOW
A.  General Conditions
1.  The Monongahela Basin
     The four impoundments of the Monongahela Basin have a pronounced effect on
the hydrology of the region.  The storage of water in the Tygart and Youghiogheny
reservoirs during peak runoff periods serves to reduce the frequency of flooding.
Deep Creek Lake and Lake Lynn, although net ocerated to provide  flood control.

-------
                                                           TABLE  2..1.5. - 10
                                                         CHARACTERISTICS  OF THE UPPER
                                                        OHIO RIVER  NAVIGATION SYSTEM
I.)
10
Locks and Dams

Emsworth

Dashiclds

Montgomery

New Cumberland
River
Mile
6.21
13.3
31.7
54. 4
State
PA
PA
PA
wv...
Dam
Crest
Gated
Fixed
Gated
Gated
Length
of Pool
(mile)
6.2
7.1
18.4*
22.7
Upper Pool
Elevation
(ft. above msl )
710.0
692.0
682.0
664.5
Surface Area
@ Normal Pool
(Acres)
1,220
1,200
2,990
3,840
Storage &
Normal Pool
(acre-feet)
18,900
17,000
57,500
74 ,000
Mean
Pool
Depth
(feet)
15.5
14.2
19.2
19.3
Commenced
Operation
Sept. 19212
Aug. 1929
June 1936
Oct. 1959
            1.  Mileage  for main channel dam

            2.  Original Construction

            *   Plus 2.6 miles of  slackwater on  the  Beaver  River


            SOURCE:  U.S. Army Corps of Engineers  (25)

-------
                                                     TABLE  2.1.5. - 11

                                         MAJOK RESERVOIRS OF THE BEAVER RIVER BASIN
RESERVOIR
Berlin
Milton
Mosquito Cr.
Meander Cr.
Michael J.
Kirwjn
Pyniatuning Lk.
Slienango
LOCATION
COUNTY, STATE
Portage, Oil
Mahoning, OH
Trunbull, Oil
Trumbull, Oil
Portage, OH
Crawford, PA
Morcer, PA
PURPOSE
FLH
L
FLW
U
FL
FLR
FLR
DATE IN
OPERATION
1942
1916
1943
1929
1966
1934
1967
DRAINAGE
AKEA
SQ. MI.
L'48
273
97.5
83.9
80.5
158
583
PERM MIN
POOL AREA
J_ACRESJ_
240
1,685
700
2,010
580
14,650
1,910
STORAGE
MAX. FLOOD
CONTROL
55,800

33,000

33,200
194,000
180,900
(ACRE-FEET)
WATER
SUPPLY
19,400

11.000
30,675



MAXIMUM
SUMMER
39 ,000
21 ,600
71 ,400

56,700
160,000
41 ,400
OPERATOR
Corps, of Engineers
City of YOUJKJS town, OH
Corps of Engineers
Mahoning Valley Sanitary
Corps of Engineers
j
I

I

Pa. Dept. Environ. Re sou re
Corps of Engineers

F - Flood Control
L - Low Flow Augmentation
W - Water Supply
R - Recreation
SOURCES:  Fed. Wtr. Poll. Cntrl. Admin.  (14) and
          U.S. Geologic Surv.  (21).

-------
 do  indeed  provide  this  service  on  chance  occasions.
      The release of water  from  the Corps  of  Engineers'  Reservoirs  during 'low'flow
 periods augments downstream  flows.   Tygart River  Lake  is  operated  to  provide a
 minimum flow  of 340 cfs  in the  Upper Monongahela  whereas  the  release  schedule  for
'the Youghiogheny River  Lake  is  designed to provide  a minimum  flow  of  200 cfs in
 the Youghiogheny River  at  Connellsville.
      During periods of  peak  power  demand, hydroelectric plants  must release  large
 volumes of water.  Discharges  from the Piney Reservoir in the Allegheny Basin  and
 Deep Creek Lake in the  Monongahela Basin  can cause  substantial  flow variation  in
 the Clarion and Upper Youghiogheny Rivers.   Hydroelectric power-induced  flow  var-
 iation  is  perhaps  best  exemplified by  the effects of Lake Lynn  discharges  when  low
 flows occur in  the Monongahela  River above its  confluence with  the Cheat River.
 During  such episodes, abrupt translator:/  waves  are  created in the  Monongahela  by
 Lake Lynn  discharges  and flows  fluctuate  widely by  the hour  (15).
      Since almost  two-thirds of the Monongahela Basin  is  located outside of
 Pennsylvania, the  flow  characteristics of the lower "onongahela are determined  to
 a  large degree  by  the hydrologic characteristics  of northern  West  Virginia and
 to  a lesser degree, Garrett  County, Maryland.   Indeed, a  mere 30"  of  the Moncngahela
 River flow at the  mouth  (Pittsburgh) originates from within  Pennsylvania  (27).
 Stream  flow characteristics  for the Monongahela Basin, determined  at  USGS  gaging
 stations for  the period  of record  prior to and  including  water  year 1976,  are  pre-
 sented  in  Table 2.1.5.-12.   Table  2.1.5.-13  depicts flow-duration  characteristics
 as  determined for  specified  years  at many of the  USGS  stations.
      It is readily apparent  from the aforementioned tables that, despite existing
 navigation and  flood-control projects, the Monongahela and Youghicgheny are  capable
 of  wide flow  variations.   However, the seasonal flow variation  of  the smaller,
 uncontrolled  tributaries is  even more  dramatic.   Many  of  these  tributaries are
 swollen, turbulent white-waters in the spring and mere trickles during  the late

-------
                                                      T  ABLE   2.1.5.  -  12
                                                    IIYOROLOGIC CHARACTERISTICS OF

                                                      MOHONGAHELA BASIN STREAMS
                                                                                                                                      AVKitAGB
IISGS
STATION
CUM1IER
CM
720
/V'j
72i.9
/2I1.4
7 JO
/45
7 '30
7U!>
76'j
77'j
7UU
V-JO
1:00
1110
H2'j
v.VJ
;MG
li'iO
STREAM
Monongahela R.
Dunkdrd Cr.
Monomjiiliela R.
Georges Cr.
Tcmiiile Cr.
South Fork
Tenmile Cr.
Redstone Cr.
Mi>non<|i'ihela R.
YOU
-------
                                                        TABLE   2.1.5.  -  13



                                                      FLOW DURATION CHARACTERISTICS

                                                           OF THE STREAMS  IN THE

                                                        MONONGAHELA RIVER  BASIN
                                                  Discharge  in cubic feet per second which was equaled or exceeded
                                                  for indicated percentage of tine.
STREAM
Munongjhela R.
Mononqjliela R.
Moiiongdhela R.
Konomj'ihela R.
Yougliioylieny R
YouyltiGyheny R
Youtjliioyheny R
Youghioghcny R
Casseliwn R.
Laurel Hill
Creel:
Dunkard Creek
South Fork
Ter.i.ii It-
Reds tone Creek
Turtle Creek
STATION
L/DO, Point Marion
Greensboro
Charlerot
Braddock
. Dam
. below Confluence
. Connellsville
. Sutersville
Markleton
Ursina
Slitinnopin
Jefferson
Waltersburg
Trafford
YEARS OF
RECORD USED
1929
1940
1934
1940
' 1939
1941
1910
1921
1921
1919
1942
1932
19-13
1920
-54
- 60
- 60
- 60
- 60
- 60
- 60
- 60
- 60
- 63
- 60
- 60
- 60
- 52
2
21 .000
35.000
42.000
52,000
3.500
7.700
1 2 .000
13.000
3,600
1.400
2,100
1.500
480
510
5
1 5 .000
26.000
29 .000
38.000
2.400
5.700
8.000
9.000
2,300
920
1.200
830
300
300
10
1 1 ,000
20.000
22.000
29,000
1.700
4.300
5,7(10
6,700
1,500
630
680
480
210
180
20
7.300
13.000
14,000
20.000
1.200
2.800
3.000
4,400
940
390
360
260
140
100
30
5.000
9,200
9.900
14,000
890
2.100
2.700
3.200
660
280
230
160
110
70
40
3.500
6.600
7,000
10.600
730
1.600
2.000
2,500
470
200
150
100
62
48
50
2,400
4.600
4,900
7.600
630
1,200
1.500
1.800
330
140
96
64
62
32
60
1.700
3.300
3.600
5.800
540
1.000
1,200
1.400
230
100
56
35
47
21
70
.1.200
2.300
2.500
4.100
450
850
850
1.100
150
68
31
19
35
13
80
780
1.500
1.700
2.900
330
680
590
800
94
42
15
6.3
28
7.4
90
570
900
1.000
2.000
220
500
350
510
50
22
5.6
2.5
23
3.8
95
470
640
740
1.600
160
350
220
380
32
14
2.9
1.2
19
2.3
98
380
480
550
1.200
120
250
130
260
21
8.8
1.8
0.7
16
1.3
SOURCE:  Adapted from Busch and Shaw (28).

-------
summer and early fall.

     In terms of velocity, the Monongahela main channel maximum (100-year flood)

is approximately 11 feet per second.  Although published averages of velocity for

the 7 day, 10-year low flow do not exist, they are estimated at 0.3 feet per second

(10).

     Approximately 25% of the Monongahela's mean discharge at Pittsburgh (12,500

cfs) originates from within the Youghiocheny Basin (29).  This percentage becomes

substantially greater during periods of low flow in the Monongahela main stem

(15).  At base flow, the Monongahela River is naturally a low-yielding stream.

Youghiogheny River water is  generally  of better quality than that of the Monongahela

Consequently, flow contributions from the Youghiocheny tend to ameliorate the

downstream-trend of water quality deterioration in the Monongahela.

     Runoff from approximately 94" of the Upper Monongahela Basin (West Virginia

and Maryland) enters ORBES Pennsylvania via the Monongahela main stem, the Cheat

River, and the Youghiogheny River Lake (27}.   The average annual runoff within

Sub-basin =19 varies from 14 inches in -he west to 28 inches in the east with an

area mean of about 19 inches.  However, the mean annual- runoff for the entire

Monongahela Basin is 22.5 inches.  Table 2.1.5.-12 includes annual runoff figures

for specific sites (USGS gaging stations) in the iMonongahela 3asin.

2.  The Allegheny Basin

     The nine Corps of Engineers' reservoirs and to a lesser extent, the Piney

Reservoir influence the hydrology of the basin by reducing flood flows by storage

of water during periods of heavy rainfall and/or intense snowmelt.  The Allegheny,

Woodcock Creek, and East Branch Reservoirs are also operated to provide low flow

augmentation by the release of stored water during periods of minimal surface run-

off.  The basin reservoirs (excepting the Allegheny Reservoir*), when considered

individually, have little influence on the flow of the lower Allegheny River (9).
*The Allegheny Reservoir has large -storage capacities for flood control  and low
 flow augmentation.

-------
Consequently, the Corps manages its facilities as an integrated system, thereby
obtaining a substantial cumulative effect upon flows in the Allegheny main.stem.
Nonetheless, several individual reservoirs do indeed regulate flow appreciably
in some of the Allegheny's tributaries.
     The flow of the Allegheny main stem is determined largely by the hydrologic
characteristics of the northern portion  of the basin, including the effects  of
the Allegheny Reservoir.  However, 12" of the average discharge at Pittsburgh
originates within the Kiskiminetas watershed (29).  This flow contribution is
significant since acid mine drainage originating in the Kiskiminetas Basin has a
detrimental effect on water quality and  aquatic ecology in the lower Allegheny.
     Decreases in stream gradient and changes in channel conformation hydraulically
serve to reduce stream velocity in the lower reach of a river.  The navigation
dams in the lower Allegheny intensify this phenomenon.  Under major flood condi-
tions (100-year flood), the maximum velocity in the slackwater pools is approxi-
mately 8-9 feet per second, whereas the  maximum velocity of the upper Allegheny
is almost 15 feet per second (9).  Under low flow conditions (7-day, 10-year low
flow), the maximum velocity of the Allegheny in flew York is approximately 7.8
miles per day (23).  Low flow velocities for the lower Allegheny are estimated to
be on the order of 5 miles per day or lower (9).
     The hydrologic characteristics of streams in the Allegheny Basin as determined
at USGS gaging stations are presented in Table 2.1.5.-14.  Table 2.1.5.-15
depicts the flow-duration characteristics of selected basin waterways at many of these
same USGS stations; changes in flow-duration are included for several stations
before and after the construction of east Branch, Piney, and Crooked Creek Re-
servoirs.  Table 2.1.5.-16 characterizes the flow,-duration of the Allegheny  main
stem at the Natrona gage (river mile 24.3).
     Average annual runoff within the Allegheny Basin ranges from approximately 18

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                                           TABLE  2.1.5. - 14

                                        HYOROLOGIC CHARACTERISTICS OF
                                        ALLEGHENY RIVER UASIN STREAMS
uses
STATION
NUMiiER
0105.
0110.2
0118
0125.5
0153
0152.8
0155
3101
0175
0? »
U;MS
0215.2
0>40
02V.)
02T.2
021.5
02? 5
U2i!0
02a5
0204
!l2'i'j
0105
0315
0325
0340
0345
OlcO
OltS

Olb'J
0300
040J
0410
0415
0420
0422.8
0425
0440
0450
0470
04I!5
0400
0405


STREAM
Allegheny R.
A) legheny R.
Kiniua Cr.
A) te<|heny II.
Cone-.6
5.69
5.9U2
73.2
63.0
204
12.6
807
951
7.6/1
528
158
87.4
344
8.973

191
278
451
183
715
192
57.4
171
1.358
172
292
1.825
137
11.410
PERIO.) OF
RECORD
(wtr. yr.)
1930-76
1903-76
1965-76
1935-76
1939-76
1962-76
1909-76
1941-76
1937-76
1941-76
1933-76
1009-76
1913-76
1933-76
19G5-76
1914-76
1948-76
HS3-/6
1945-76
1959-76
1938-76
1944-76
I932-/6
1918-76
1938-76
• 1939-76
1939-76
1905-28.
1914-76
1937-76
1909-76
1930-76
1940-76
1939-76
1952-76
1967-76
1952-76
1919-76
1930-76
1019-76
1916-76
1940-76
1938-76

AVERAGE '
DISCI IARG£(cfs)
941
2,777
76.8
3.803
1.475
23.4
579
6.519
457
869
52G
422
1.770
270
0.91
10.370
133
122
377
19.1
1.434
1.745
13.220
856
273
150
509
15.5/0

2U7
421
765
322
1.2C5
360
107
276
2.349
301
480
3.058
(90
19.240
INSTANTANEOUS
MAXIMUM (cfs)
AND DATE (mo/yr)
65.400-6/72
73.000-6/72
5.220-6/72
60. SCO- 3/56
14.400-4/47
1.020-3/72
18,000-3/13
101.000-3/56
15.000-1/59
13.500-3/64
21.000-1/59
20.000-4/47
23.UOO-3/64
10.000-5/46
1.650-7/72
138.000-3/20
2,590-5/57
5.400-9/67
11.700-5/46
656-3/64
53.300-6/72
74.500-6/72
175.000-1/59
50.000-3/36
17.300-6/72
6.200-6/72
10,400-3/42
209.000-3/13

13.200-6/72
21.000-3/36
59.000-3/36
16.600-6/72
M, 000- 10/54
20.800-6/72
4.100-6/72
19.600-6/72
59.200-3/45
29.700-10/54
II. 700-6/4)
71.900-3/40
14.0UO-1IJ/54
238.000-12/42
MINIMUM DAILY
(cfs) AND
DATE (mo/yr)
—
79-9/71
—
—
57-10/60
—
—
-,--
—
0.4-2.5.6/68
—
—
—
—
—
—
0.40-7/69
—
20-10/48
0.31-8/71
—
—
—
—
—
—
—
—

I.O--IO/66
—
—
—
105-12/38
—
—
8.7-9/52
1-9/54
0.2-16/53
0. 2-10/47
60-10/52
—
—
INSTANTANEOUS
AVERAGE
MINIMUM (cfs) ANNUAL RUNOFF
AND DATE (cno/yr)
22-9/59
—
4.0-9/66
—
—
0.4-10/63
19-10/34
—
11-8/62
—
22-7.9/34
3.9-8/30
43-7/34
9.2-10/35
0.42-IO/CG
334-7/34
0.20-7/69
4.2-9/55
6-9/52
—
41-8/39
—
409-7/31
19-10/18
2.6-9/39
0.3-9/59
8.8-9/59
570-9/13

—
0.1-9/32
5-9/29
3.4-9.10/63
—
19-9/52.11/53
1.4-7/69
2.0-9/52
n/h
0.1-9/53
0.2-10/47.9/48
56-10/52
1.3-10/60
895-10/63
(In)
23.23
23.45
22.48
23.69
24.54
24.67
24.50
24.19
24.94
24. t4
23.81
26.05
23.38
22.00
21.26
23.54
25.04
26.30
25.10
20.59
24.13
24.92
21.40
22.02
23.46
23.31
23.25
23.56

20.41
23.57
23.03
23.90
24.03
25.46
25 32
21.92
23.49
23 76
22 32
22.75
18.83
22.90
 • Hesull of Aunorinol  Regulation
SUUDCF: Adapted fiwU.S. Ccol. Survey (21).
I.   Stations downstream of impoundments regulated
    for storage

-------
                                                  TABLE 2.1.5.-15

                                        FLOW DURATION CHARACTERISTICS
                                            OF THE STREAMS IN THE
                                            ALLEGHENY RIVER DAS IN
                                                Discharge in cubic feet per second which was equaled or exceeded
                                                for indicated percentage of tine.

STREAM
Tionesta Cr.
0)1 Cr.
French Cr.
Sugar Cr.
Allegheny R.
E. Ur. Clarion

W. Dr. Clarion
Clarion R.

Clarion R.
Clarion R.

Clarion R.

Clarion R.
liedbdiik Cr.
Muhoning Cr.
Little Mjhoning
Mahoning Cr.
Crooked Cr.
Crooked Cr.

Stony Cr.
Little
Conenuiugh R.
Concilia ugh R.
niacklick Cr.
Two Lick Cr.
niacklick Cr.
Loyalhdima Cr.
Kiskimiiietas R.
Buffalo Cr.

STATION
Below Dam
Rouseville
Utica
Sugarcruek
Frankl in
Below Dam

Wilcox
Johnsonburg

Ridywjy
Cooksburg

Piney

St. Petersburg
St. Charles
Puiixsutawney
McConuick
fie low Dam
1dilhO
Below Duin

Ferndale
East
Concnuugh
Scv/ard
Josephine
Grace ton
Bldcklick
Kingston
Vandergrift
Freeport
YEARS OF
RECORD USED
1941-60
1933-60
1933-60
1933-60
1931-63
1949-52
1953-60
1954-60
1946-52
1953-60
1941-53
1939-52
1953-60
. 1949-52
1953-60
1942-53
1919.1922-57
1939-60
1940-60
1939-60
1938-60
1919-40
1941-60
1914-35.40-60

1940-60
1939-60
1953-60
1951-60
1905.00-51
1941-60
1938-60
1941-60

2
4,900
3,000
8.800
1.500
49 ,000
720
500
610
2.100
1 .600
3 .000
7.500
6.100
9.600
7.500
11,000
4.600
1.400
900
3.100
1.800
2 .800
2 .600
3.700

1.500
5.900
1 .800
1,500
3.800
1.600
14.000
1.200

5
3.300
1.900
6.200
950
35 .000
490
290
400
1 .400
,.000
2.000
4,900
4,200
6.800
5,300
7.500
3,100
910
560
2.000
1 ,1110
1 ,600
1.700
2.400

930
4.000
1 .100
960
2.400
1 .000
10.000
730

10
2.300
1.200
4.400
610
26,000
360
240
280
UflO
720
1.400
3.500
3.100
4 ,900
3,900
5,500
2.100
620
360
1,500
710
1 .000
1 .100
1,600

640
2,800
850
650
1,600
750
7,200
470

20
1.400
740
2.000
380
16.000
240
210
180
t)30
470
900
2.300
2.100
3,200
2.600
3.600
1.300
400
220
890
410
530
720
970

420
1.000
540
400
990
440
4.700
280

30
930
G10
1.900
270
11.000
180
170
130
470
380
620
1.600
1.600
2.300
1.900
2 .600
T.40
280
150
600
270
.140
440
650

290
1,300
370
/RO
660
310
3.300
190

40
710
360
1,300
190
7,900
130
130
96
340
310
440
1.100
1.200
1.600
1.400
1.800
580
200
100
420
190
230
260
450

200
920
260
200
470
220
2.400
130

50
440
270
910
140
5.400
90
83
77
220
250
310
800
920
1.100
1.100
1.200
400
140
70
290
130
150
190
310

140
670
180
140
340
160
1,700
90

60
240
190
620
100
3,800
56
45
57
160
230
230
540
690
680
800
840
270
100
47
200
84
94
120
220

96
530
130
90
240
110
1,300
59

70
200
140
410
72
2.600
29
28
41
95
200
160
360
520
350
560
540
180
68
30
140
53
50
76
150

66
420
95
59
160
72
900
35

80
120
90
240
48
1.600
18
22
25
57
160
92
220
380
170
370
330
110
44
15
85
31
33
44
94

42
330
68
38
100
41
650
19

90
76
54
140
32
1,000
12
18
14
35
100
54
130
270
64
130
170
72
29
6.6
46
16
17
24
50

20
250
43
22
62
19
440
9.2

95
58
44
110
25
770
9.5
16
10
29
45
42
100
150
30
27
97
53
24
3.9
31
11
9.0
17
31

13
210
34
17
44
10
360
6.6

98
42
36
84
21
640
8.0
14
6.4
26
32
35
78
97
26
24
66
41
20
2.4
22
7.7
4.3
12
21

8.8
190
29
14
31
3.5
290
4.9
SOURCE:  Adapted from Busch and Stiaw (28).

-------
                         TABLE  2.1.5.  -16
                   FLOW - DURATION CHARACTERISTICS^
                   THE ALLEGHENY RIVER AT NATRONA,  PA?
Discharge                                     Percent  of  Time  Flow
  fcfs")                                       Equaled  or  Exceeded
 1,000                                              100.0
 2,000                                              100.0
 3,000                                              99.0
 4,000                                              85.8
 5,000                                              75.9
 6,000                                              66.2
 7,000                                              60.8
 8,000                                              56.5
 9,000                                              53.1
10,000                                              50.0
11,000                                              47.1
12,000                                              44.7
13,000                                              42.6
14,000                                              40'. 6
15,000                                              38.7
16,000                                              37.0
17,030                                              35.5
18,000                                              34.0
19,000                                              32.6
20,000                                              31.3
 aFor present conditions of development  (April  1975)
 bRi
-------
inches in areas near Pittsburgh to sites yielding 25 inches at French Creek and
the West Branch of the Clarion River (21,30).   Table 2.1.5.-14 includes annual
runoff figures for USGS stations within the basin.  Runoff is more or less homo-
geneous in the upper portion of the basin:  however, runoff tends to decrease
from east to west in the middle and lower sections; reflecting changes in the
distribution of precipitation (30, 31, 32).
3.  The Upper Ohio Basin (Pa.)
     Approximately 60% of the Ohio River's  mean discharge at Pittsburgh is con-
tributed by the Allegheny River, the remaining 40* is contributed, by the Monongahela
(29).  The flow of the Ohio for its first 25 miles is chiefly governed by the con-
tributions of these two streams since Chartiers Creek is the only other signifi-
cant tributary to this reach.
     At Rochester, the Beaver River makes a significant contribution (mean discharge
= 3,250 cfs) to the flow of the Ohio River.  The Beaver Basin is an intensively
regulated area; it contains 713,000 acre-feet of storage space in a land area of
3,150 square miles.  Flood control and low flow augmentation are dual purposes in
the operation of five of the basin's seven  major reservoirs.  Milton Reservoir is
operated for low flow augmentation alone (see Table 2.1.5.-11).
     Table 2.1.-17 depicts the hydrologic characteristics of streams at the major
USGS gaging stations in the Ohio and Beaver Basins.  Table 2.1.-13 presents the
flow-duration characteristics at many of these same stations.  Flow-duration of
the Ohio main stem at the Sewickley gage is graphed in Figure 2.1.5.-5.
     Annual runoff within Sub-basin ?20 ranges from 14 inches in the west to areas
yielding approximately 20 inches in the east (24).  However, individual sites,
such as the Ohio River at Sewickley may yield annual runoffs as high as 22.5 inches.
Table 2.1.5.-17 includes annual runoff data for this sub-basin.

-------
                                                                         TABLE  2.1,5. - 17
                                                                HYDROLOGIC CHARACTERISTICS OF
                                                              OHIO RIVER MAIN  STEM AND  TRIBUTARIES
uses
STATION
NUMBER
855

860
rnn
1015
10?5
1028.5
1U3G
I0'j5

1060
IOG5
1075
I0f!0
1111.5
1300
STREAM
Chartiers Cr.

Ohio R.
Big Sewickley Cr.
Shenanijo R.
Little Shenango R.
Shenango R.
Shcnaiiijo It.
Beaver H.

Connoi|uenessing Cr.
SIippery Rock Cr.
Beaver R.
Raccoon Cr.
Brush Hun
Conneaut Cr.



LOCATION*
Carnegie

Scwickley
Amb ridge
Pymatuning Oam
Greenville
Transfer
Sharpsville
Udnipum

2el ienople
Wurteudjurg
Heaver Falls
MolfaUs Mill
Buffalo
Conneaut, OH

DRAINAGE
AREA 0
GAGE
(sq. mi.)
257

19.500
15.6
167
ion
337
581
2.235

356
308
3.106
178
10.3
175


PERIOD OF
RECORD
(wtr yr.)
1919-33.
1940-76
1933-76
1967-76
iyjb-76
1913-76
1965-76
19311-76
1915-18.
1933-76
1919-76
1911-76
1935-76
1912-76
196t-76
1923-34.
1950-61


AVERAGE **
DISCHARGE (cfs)
287

32.370
17.7
199
140
455
7?6
2,394

467
563
3.545
190
9.26
257


INSTANTANEOUS
MAXIMUM (cfs)
AND DATE (mo/yr)
13.500-8/56

574.000-3/36
2.540-7/75
1.540-9/37
8.540-1/59
5.200-2/76
15,700-1/59
50.100-5/46

23.000-6/24
19.000-1/37
69.900-1/59
ft. 590-1/52
1.180-2/66
17.000-1/59

                                                                                                   MINIMUM DAILY
                                                                                                   (cfs) AND
                                                                                                   DATE (mo/yr)
43-9/41
97-7.8/33
              INSTANTANEOUS
              MINIMUM  (cfs)
              AND DATE  (mo/yr)
  16-8/26.9/32

,800-9/57
   0-often
 0.1-6/34
 2.9-7/34
  33-7/68

  74-7/33

   6-7/36
  16-9/32

 4.5-8/65
   0-otten
 0.2-7,8/33.8/34
AVERAGE
ANNUAL
RUNOFF

  (in)


  15.17

  22.54
  15.41
  16.10
  18.28
  18.34
  16.88
  14.55

  17.81
  19.21
  15.50
  14.50
  12.21
  19.95
             Pennsylvania  locations  unless  otherwise  designated
             Adjusted for  storage where  applicable
          SOURCE: Adapted from U.S. Geological Survey (21).

-------
                                                                      TABLE  2,1.5. - 18

                                                                    FLOW DURATION  CHARACTERISTICS
                                                                        OF THE  STREAMS  IN  THE
                                                                       UPPER OHIO  BASIN (PA.)
                                                                           Discharge in cubic feet per second which was equaled or exceeded
 i -
ui

STREAM STATION
Shenango River Turnerville
Sugar Run Pymatuning Dam
SliL'nango R. Pyniatuning Dam
Shciungo R. Jamestown
Little Shcnango Greenville
Sheiuini|o R. Sharpsville
SlienaiMjo «. New Castle
BIMVLT R. —Wampum
Conmuiui-nessing ?el ienople
Slippery Rock Wurti.-mhurg
Raccoon Cr. Mot falls Mill
YEARS OF
RECORD USED
1913-22
1941-GO
1935-60
1920-33
1915-60
1939-60
1939-60
1933-60
1920-60
1912-63
1942-60
for indicated
2
1.300
92
850
1.200
800
3.600
5.100
13,000
3.000
3.100
1.100
5
730
46
680
840
550
2.400
3.300
fl.300
1 .800
2,000
700
10
470
25
500
600
330
1.800
2.200
5.700
1.200
. 1 .400
460
20
280
12
280
370
190
i.ioo
1.400
3.300
630
840
290
percentage of time.
30
170
7.0
220
230
120
770
900
2.200
450
5-10
200
40
110
4.3
190
140
86
510
560
1 .600
300
370
140
50
77
2.5
150
96
61
360
380
1.200
200
260
98
60
53
1.3
110
58
42
290
240
980
130
170
68
70
30
0.6
75
32
28
250
140
820
80
120
47
80
16
0.3
36
16
18
210
83
630
47
84
31
90
8
0
10
8
11
170
44
450
26
59
19
90 98
.7 6.7 5.1
.Ob 0.02 0
3.8 2.0
.2 5.4 4.0
8.3 6.5
130 110
30 22
340 220
18 13
47 38
14 10
           SOURCE: Adapted  from Uusch and Shaw (28).

-------
1,000,000'
 100,000-
 o
  10,000-
  1,000-
                      FIGURE 2.1.5. - 5
                                                                 . 1,000.000
            DURATION  CURVE
              OF FLOWS  FOR
              SEWICKLEY,  PA.
                     PERIOD OF RECORD

                     	\ Jon J946 lo 31 Det 1975

                     	1 July «975 lo 30 Juno 1976
           10
              PERCENT TIME FLOW LESS THAN OR EQUALED

     SOURCE: ORSANCO (3'J) .
                                                -100,000
-10.000
20     30     40     50     60    70    80     90     100
                                                                  1,000

-------
     Travel times during various flow regimes in four reaches of the upper Ohio
River upstream of Cincinnati, Ohio have been calculated by the U.S.  Geological
                                •
Survey (34).  Figure 2.1.5.-6 graphs the average times of travel as  a function
of flow at Cincinnati for each of these reaches.  During low flow conditions<
however, such calculations may be inaccurate due to the effects of wind action,
diffusion, and lock operation.
B.  Extreme Conditions
1.  Floods
     In the 46 years from 1900 to 1945, 64 floods occurred at Pittsburgh, an aver-
age of 1.4 floods* per year (35).  Approximately 70% of these floods were exper-
ienced from January to March.  Another analysis (3), extending back  in time to
1885 has indicated that prior to the construction of flood-control reservoirs,
Pittsburgh could anticipate high waters, which would cause at least  minor flooding
on an average of 1.3 times per year.  Table 2.1.5.-19 lists the great floods of
the major ORBES-Pennsylvania waterways from 1763 to 1963.  Numerous  floods of
slightly less than maximum gage height have been purposely omitted to focus
attention on the most severe episodes.
     As early as 1912 the Pittsburgh Flood Commission had recommended construction  •
of 17 flood-control reservoirs in the upper reaches of the Monongahela and Allegheny.
However, no such projects were in operation in March of 1936 when the devastating
and memorable "St. Patrick's Day Flood" hit Pittsburgh.  Caused by a combination
of river ice James, melting snow and rain, this flood remains the worst on record
for the Pittsburgh metropolitan area.  The flood crested at 46.0 feet, exceeding
by 4.9 feet the previous record set in 1753.  Although the upper reaches of the
Monongahela and Allegheny rivers did not reach maximum flood stage,  their tribu-
taries near Pittsburgh (Red Bank Creek, Kiskiminetas River and Youghiogheny River
were at record high levels concurrently (36).
*"Flood stage" is 25 feet at the Pittsburgh gage.  No one knows exactly why this
 particular elevation was  chosen; and it is meaningless today since no real
 damage occurs until the water level exceeds 27 feet, a level reached 43 times  in
 the 46 year study period.

-------
                           FIGURE   2.1.5.  • 6



                      RELATION OF DISCHARGE AT CINCINNATI TO

                  AVERAGE TRAVEL TIME  OF  WATER FROM PITTSBURGH
oSOO

5
£700
5600

u
  500
o
  400
u300
z
0
£200
  100
                    100             200              300             400
                       AVERAGE TIME Of TRAVEL FROM  PITTSBURGH. IN HOURS
300
        SOURCE:  U.S.  Geological  Survey (34).

-------
                                            TABLE  2.1.5.  -'19

                                   GREAT FLOODS Ofl MAJOR RIVERS
                                   OF  WESTERN PENNSYLVANIA
RIVER
Honongahela
Youghiogheny
Allegheny
Kiskinrinetas
Ohio
STATION
Charleroi
Connellsville
Kittaning
Avoninore
Pittsburgh
DATES
July 11, 1888
, 1887
March 18, 1936
October 16, 1954
August 21-22, 1888
March 14, 1907
March 29, 1924
March 18, 1936
October 16, 1954
April 10, 1806
March 18, 1865
February 5, 1883
March 20, 1905
March 26, 1913
August 21 , 1888
June 1 , 1889
February 17, 1891
March 14, 1907
March 18, 1936
March 9, 1763
February 10, 1832
February 6, 1884
March 15, 1907
March 18, 1936
GAGE HEIGHT
(ft.)
26.1
24.5
22.47
21.07
17.8
.18.4
20.5
20.28
21.96
30.0
29.5
29.0
28.8
30.7
31.8
29.8
30.4
33.8
47.2
41.1
38.0
36.3
38.5
46.0
COMMENTS
Bankfull stage,
24' gage
Bankfull stage,
16' gage
Bankfull stage,
23' gage
Floodstage, about
27' gago
Floodstage, about
25' gage
SOl)KCI':: Adapted  from Shank (3f>).

-------
     Total damages'wrought by the 1936 flood were greater than any previous or
subsequent water disasters in the Pennsylvania-ORBES region.  The Duquesne Light
Company's power generating system, although designed to operate under flood con-
ditions greater than those of past records, was unable to provide normal service
to the City of Pittsburgh for eight days (37).
     Flood-control reservoirs in the Monongahela and Allegheny Basins reduce flood
crests by 2-4 feet and 4-10 feet respectively in each of the main stems from
what would be normally expected without such flood control measures (9, 10).
It has been estimated that the St. Patrick's'Day Flood would have had its crest
reduced by 10.1 feet at Pittsburgh, if only the first eight flood control reser-
voirs to be constructed were in operation in 1936 (3).  This analysis does not
even consider the additional reduction "hat would be afforded today by the pre-
sence of the large Allegheny Reservoir.  Nonetheless, despite structural flood
control measures, flood damages have exhibited a tendency to increase along with
urbanization.  This trend has been ascribed mainly to inadequate enforcement of
flood plain regulations (38),
     Information on flood discharges from several floods in the Allegheny and
Monongahela Basins is presented in Tables 2.1.5.-20 and 2.1.5.-21.  Tables 2.1.5.-
22 and 2.1.5.-23 relate flood flows to surface elevation in these two rivers.
     An examination of recorded high flew maxima reveals that floods can occur at
virtually any time of the year.  However, studies of the relationships between
factors influencing flood occurrence (storm duration, intensity, affected area,
and seasonality) indicate that the large streams tend to flood in the winter
whereas small tributaries have a propensity to produce summer floods.  Reich (39)
demonstrated by analysis that Pennsylvania watersheds greater than 100 square miles
had up to one-third of their annual floods in March.  Regional storms bring abun-
dant precipitation to the area in late winter and early sprinq.  Furthermore, runoff

-------
                         TABLE  2.1.5.  -20

                            ALLEGHENY RIVER
                      DISCHARGES FOR VARIOUS FLOODS
    Station

Lock and Dam No. 4
(Natrona Gage)

Lock and Dam No. 7
(Kittanning Gage)

Parker, Pa.

Franklin, Pa.
	Actual Discharge in 1,000 cfs	
Jun. 1972   Jan. 1959  Mar. 1964  Mar.  1936
  225.0


  189.3

  161.1

   86.2
245.0


207.7

182.0

126.3
240.0


213.8

163.0

106.6
360.5
201.9
Source:  U. S. Array Corps of Engineers (9).

-------
                       TABLE  2.1.5. - 21

                           MONONGAHELA RIVER
                      DISCHARGES FOR VARIOUS FLOODS
                                            Actual Discharge  in  100Q c£s
     Station

Lock & Dam No. 2
Braddock Gage

Lock & Dam No. 4
Charleroi Gage

Maxwell Lock & Dam

Lock & Dam No. 7
Greensboro Gage

Morgantbwn Lock & Dain
 June
 1972
180.0


130.9

120.0
 March
 1967
178.0


158.0

158.0
107.0     145.0

 31.1    •  85.0
March
1963
163.0


154.0

154.0


134.5

 77.0
Source:  U. S. Ar:ny Corps of Engineers  (10)

-------
                                                      TABLE   2.1.5.  -22

                                                  FLOOD  FLOWS  AND ELEVATIONS3
                                                        ALLEGHENY RIVER
VJl
  Flood Frequency

1 year flow (cfs)
Upper pool elevation
(ft. above msl)

5 year flow (cfs)
Upper pool elevation
(ft. above msl)

50 year flow (cfs)
Upper pool elevation
(ft. above msl)

100 year fJow (cfs)
Upper pool elevation
(ft. above elevation)
Stations
Lock & Dam
No. 4
Natrona Cage
93,000
753.6
139,000
756.8
210,000
762.1
233,000
763.4
Lock & Dam
No. 7
Kittanning Gage
90,000
790.9
132,500
793.6
196,000
797.0
215,500
798.2
Parker, Pa.
Gage
70,000
858.3
107,000
862.3
157,000
867.1
173,000
868.3
Franklin, Pa.
Gage
50,400
968.1
72,000
970.7
110,000
974.5
121,500
975.8
           aFlows and elevations  based on  existing  basin  development and existing river
            conditions  (April  1975).
           SOURCE:  Adapted  from U.  S. Army Corps  of  Engineers  (9).

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                                                     TABLE  2.1.5.  - 23

                                                 FLOOD FLOWS  AND ELEVATIONS3
                                                      MONONGAHELA RIVER
                                                                   Stations
ui
i--
 Flood Frequency

1 year flow (c£s)
Upper pool elevation
(ft. above msl)
Lower pool elevation
(ft. above msl)

5 year flow (cfs)
Upper pool elevation
(ft. above msl)
Lower pool eJcvation
(ft. above msl)

50 year flow (cfs)
Upper pool elevation
(ft. above msl)
Lower pool elevation
(ft. above msl)

100 year flow  (cfs)
Upper pool elevation
(ft. above msl)
Lower pool elevation
(ft. above msl)
Lock & Dam
No. 2
Braddock Gage
104,900
730.0
	
145,000
733.0
	
205,000
738.4
	
220,800
740.1
Lock & Dam
No. 4
Charleroi Gage
82,000
745.4
	
1 19 , 300
751.2
	
167,000
757.8
	
182,500
759.6
Lock & Dam
No. 7
Greensboro Gage
73,000
788.2
	
107,500
791.8
	
157,000
798.2
	
168,000
799.4
Maxwell
L/D
79 , 300
	
758.6
115,800
	
765.4
164,000
	
773.2
178,100
	
Morgan town
L/D
33,000
	
802.5
55,000
	
806.7
92,000

812.5
104,000
	
                                                                                        775.3
814.0
          al-'lows and elevations based on existing basin  development  and  existing river conditions (April 1975)

          SOURCE:  U.S. Army Corps of Engineers  (10)

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(snowmelt often included) is high due to the impervious state of the soil  (sat-
urated or frozen).  Conversely, small watersheds were shown to have their highest
probability of flooding in August.   Such findings support the notion that small
tri ubtary basins are susceptible to flash-flooding from local summer thunder-
showers.
     Flash-floods are often partially attributed to steep tomography.  However,
land use can substantially modify this tendency.  Although the Allegheny Mountain
Section of the Monongahela Basin is steeper than the Pittsburgh Plateau Section,
a. study comparing equivalent drainage areas in each section revealed insignificant
                             ! •
differences in flood response (40).  The higher degree of forestation in the more
mountainous area is believed to be the equalizing factor.  The effects of forest
cover on hydrology are discussed in greater detail in Section 2.1.4. (Terrestrial
Ecology).
2.  Low Flow
     Stream flow in the Appalachian Region is generally quite plentiful, averaging
about 350 million gallons per year per square mile of drainage basin (41).  Al-
though low flow augmentation is a consideration in the release schedules of ten
reservoirs that regulate stream flow in the Pennsylvania ORBES region, area water-
ways are nevertheless capable of developing flow deficiencies during periods of
drought.  An analysis of the annual cyclical variations in stream flow reveals
that low flow conditions are most likely to occur in the late summer and early fall
(August, September, October).  Most USGS stations have their record minima logged
for these months (see Tables 2.1.5.-12, 2.1.5.-14, 2.1.5.-17).  When drought con-
ditions persist, surface runoff is virtually nonexistant and small unaugmented
streams rely almost totally on  ground water for their flow.  Unfortunately, the
level of ground water storage is typically also at its lowest level during this
time of the year.

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     Minimum stream flows may vary substantially from one year to the next.  Var-

iations in low flow usually range from zero to about 1.2 cfs/sq. mi. within a two
                •
year period.  A generalized geographic distribution pattern of average annual

low flows is presented in Figure 2.1.5.-7.

     The 7-day, 10-year low flow is a widely used basis for allocating waste

loadings to a stream; it represents the flow expected to occur annually with a ten

percent probability.  Estimations of such flows for sites in each of the basins

are given in Tables 2.1.5.-24, 2.1.5.-25 and 2.1.5.-26.  More detailed statistical

manipulations of low flow data including low flow frequency curves, yield-storage-

frequency relationship curves, and low flows for various durations and recurrence

intervals are available in two publications (28, 44) of the Pennsylvania Depart-

ment of Environmental Resources.

     The Ohio River Valley Water Sanitation Commission (ORSANCO) has noted that the

activities of the Corps of Engineers have increased the 7-day, ten-year low flow

of the Ohio River.  Likewise, the minimum 7-day running averages of flow at

Sewickley, Pennsylvania (r.m. 11.8) have been increased since 1967 due to the

operation of the Allegheny Reservoir (see Fig. 2.1.5.-8).  However, the 7-day

running averages of flow at Sewickley have remained unaffected by releases from

this large impoundment (see Fig. 2.1.5.-9).  Moreover, trend analysis extending

from 1953 to 1975 indicates no net change in flow.

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                       F I G U R 3  2.1.5. - 7

                   LOW FLOW VARIABILITY IN WESTERN
                           PENNSYLVANIA
    EXPLANATION
                                      COWAMP Study Area No. 9
  0-0.1

0.1-0.2

0.2-0.4

  >0.4
                                     1
                                           1500
                                           2000  AND OVER
   Average annual
   low  flow
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                                TABLE  2.1.5. -  24

                             7-DAY,  10-YEAR  LOW FLOWS
                          IN  THE MONOXGAHELA RIVER  BASIN
   USGS
 Station
 Number
  720



  725

  730


  745

  750

  765



  780

  790

  800

  810

  825



  835



  845

  850
    S tream

Monongahela R.

Dunkard Cr.

Cheat R.

Monongahela R.

South Fork
Ten Mile Cr.

Redstone Cr.

Monongahela R.

Youghiogheny R.

Youghiogheny R.

Casselman R.

Casselman R.

Laurel  Hill Cr.

Youghiogheny R.

Youghiogheny R.

Youghiogheny R.

Youghiogheny R.

Monongahela R.

Turtle  Cr.

Monongahela R.

Monongahela R.
     Location*

Pa.-W.Va. State Line

Shannopin

Below Lake Lynn

Greensboro

Jefferson


Waltersburg

Charleroi

Friendsville, Md.

Above Reservoir

Grancsville, Md.

Markleton

Ursina

Confluence

Connelisville

Above Jacobs Cr.

Sutc-rsville
      /
Above Yough. R.

Traffcrd

Braddock

Near Mouth
 7 Day,
10 Year
Low Flow

   330

..:.-  0.6

    38

   400

   0.2


    13

   420

    47

    50

   1.0 .

    14

   4.6

   220

   240

   245

   310

   310

   0.6

  1,000

  1,010
 *Pa.  location unless specified otherwise

 	Extrapolations from existing USGS stations

SOURCE:  Busch and Shaw (28) and Ohio River Basin Corliss i.jn (42)

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                                TABLE  2.1.5.  - 25
                            7 DAY,  10 YEAR LOW FLOWS
                                     IN THE
                              ALLEGHENY RIVER BASIN
 uses
Station
Number

 105

 205

 240

 250

 255

 280
 325

 340

 365

 390

 415

 420
 490

 495
    Scream

Allegheny R.

Oil Cr.

French Cr.

Sugar Cr.

Allegheny R.

West Br. Clarion

Clarion R.

Clarion R.

Redbank Cr.

Mahoning Cr.

Allegheny R.

Crooked Cr.

Conemaugh R.

Blacklick Cr.

Blacklick Cr.

Loyalhanna Cr.

Buffalo Cr.

Allegheny R.
  Location*

    Eldred

    Rousevilla

    Ucica

    Sugarcreek

    Franklin

R.  Wilcox

    Ridgway

    St. Petersburg

    St. Charles

    Punxsutavney

    Kittannicg

    Below Dam

    Seward

    Josephine

    Blacklick

    New Alexandria

    Freeport

    Natrona
*?ennsylvania
                        Natural
7 Day,      7 Day,      7 Day,
10 Year     10 Year     10 Year
Low Flows3  Low Flows*3  LpwFlpws0
    23

    28

    60

    15
   4.2

    26

    53

    30

    15



   4.3

   165

    25

    23

    14

   3.1
             2,500
              470
2,700
750 - 778
             2,900
            900 - 1,096
  SOURCES:  a.)  Busch and Shaw (23), periods of analysis specified therein;
           b.)  U.S.  Aray Corps of Engineers (9); c.)  Fed.  wtr.  Poll.  Cntrl.
               Admin. (14)  and the U.S.  Amy Corps of Engineers (9),  represent;
               low flows without augmentation from reservoir?.

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                                 TABLE  2.1.5-  - 26
                             7 DAY,  10 YEAR LOW FLOWS
                       IN THE UPPER OHIO AND BEAVER BASINS
USGS
Station
Number
855
860
861
995
1015
1025
1028.5
1035
1055
1060
1065
1075
1080
1111.5
Stream
Ohio R.
Chartiers Cr.
Ohio R.
Big Sewickley Cr.
Mahoning R.
Shenango R.
Little Shenango R.
Shenango R.
Shenango R.
Beaver R.
ConnoquenesSing Cr.
Slippery Rock Cr.
Beaver R.
Raccoon Cr.
Brush Run
Location
Pittsburgh
Carnegie
Sewickley
Amb ridge
Lowellvilla, OH
Pyman tuning Dam
Greenville
Transfer
Sharpsville
Wampum
Zelienople
Wurtemburg
Beaver Falls
Moffatts Mill
Buffalo
7 Day, 7 Day>
10 Year 10 Year
Low Flow3 Low Flowb
5,050 6,555
25
6,600
0.0
290
14
5.4
29
81
270
10
30
560
7.4
0.0
Natural
7 Day,
10 Year
Low Flowc


1,800












 *Pa.  location unless otherwise specified.
—Extrapolation from existing USGS stations.
 a.   The existing 7 day,  10 year low flow is  that provided by the Army and represents
     the flow which would result from the 1968 A Reservoir System minus Rowlesburg
     Lake.   SOURCE:  Ohio River Basin Commission 
-------
loo.oocH
  O
  Li.
 10,000-)
  1,000-
                              F I G I) R  E   2.1.5. - 8

                            SEVEN DAY RUNNING AVERAGES  OF FLOW
                                AT SEWICKLEY, PA.
                    -- J
                                                     MINIMUM 7 DAY RUNNING
                                                     	 1 Jon 1967 lo 31 Dec 1975
                                                     	1 Jon 1946 lo 31 Doc 1975
'   JAN   '
'  MARCH  '    APRIL
tPI
                                                                                                                        JUNE
                                                            TIME
        SOURCE: ORSANCO (33)

-------
  100.000-
o
  10.000-
   1.000
              FIGURE  2.1.5. - 9

               7  DAY RUNNING
              AVERAGE  FLOW AT
                SEWICKLEY, PA.
              1
PERIOD OF RECORD
J DAY RUNNING AVERAGE
	 1 July 1975 lo 30 June 19

	 I Jon 1946 lo 31 Dot 197!


	 I Jon 1967 lo 31 Dot 1975

     	1	r—
         JULY     AUG     SEPT     OCT     NOV     DEC     JAN

                                                TIME

     SOURCE: ORSANCO (33) .
	1	1
 FEB     MARCH   APRIL

-------
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