EPA Region III
Storm Water Data Subgroup
Report and
Recommendations
October, 2001
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1
TABLE OF CONTENTS
Introduction 2
Overview of Environmental Impacts 2
Studies on Effects of Urbanization on Aquatic Systems 8
Special Issues: 11
- Impervious Surfaces and Groundwater
- MS4s and Construction Activities
Summary of Storm Water Sources, Impacts and Regulatory Controls 12
Water Quality Assessments: Results and Analysis 15
Chesapeake Bay Characterization 20
Indicator Development 25
Targeting Areas for Enforcement and Outreach 26
Conclusion and Recommendations 29
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2
Introduction
This report on storm water data presents an overview of existing EPA data and research efforts on
storm water impacts. The report proceeds from a broad overview of land development spurred by
population growth which creates environmental conditions that result in storm water having
detrimental effects on aquatic habitat and organisms. Key findings from research studies on aquatic
impacts are presented and special issues are discussed relating to stormwater sources and
groundwater. Regulatory controls are connected to sources of storm water and their impacts and
water quality assessment results and presented and analyzed. A framework for environmental
indicator development is presented as well as a targeting strategy for focusing resources on the most
critical and sensitive areas. Recommendations for specific work efforts to support the regional storm
water strategy are presented.
Overview of Environmental Impacts
Ongoing development of suburban areas presents a continuing source of environmental stress
primarily through loss or modification of habitat. Other development-related stresses result from
storm water runoff at construction sites, stream channelization, stream flow alterations, forest
fragmentation, and increases in impervious surface area.
FOREST FRAGMENTATION
Forests play an important role on landscapes both natural and developed. They benefit human uses
and wildlife species, providing wood fiber, outdoor recreation, wildlife habitat and regulation of
certain hydrologic processes. Forests produce tremendous amounts of energy, nutrients, and oxygen,
and affect regional weather and global climates. Overall, about 70% of EPA Region III is forested
and a majority of the watersheds in Region III have over 60% forest cover. Forest fragmentation is a
significant environmental concern in the Region III. It refers to formerly continuous forest that has
been broken up into smaller pieces. Substantial differences exist between broken-up and continous
forests in their ability to support wildlife species and communities and to maintain a sustainable
forest ecosystem.
Legend / fragmentation index (%)
| Less than 7.8
| 7.8 to 11.2
~ 11.2 to 13.8
I 13.8 to 21.4
f Mnrf thnn 91 4
Forest fragmentation is highest in watersheds around the Chesapeake Bay area
and in western Pennsylvania in the major urban centers of the region
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3
In the eastern United States, forest loss is generally associated with conversion to agricultural and
urban/suburban land uses. Increasing forest fragmentation is closely related to population change: as
the population increases, the need for developed land increases resulting in more forests converted to
agricultural and urban /suburban uses.
Environmental Problems associated with Forest Fragmentation
The degree of connectivity of a forest can affect the sustainability of forest species within or among
watersheds. Areas with large blocks of continuous forests support a wide variety of forest species,
whereas areas with small, fragmented forests support fewer interior species. Interior forest habitats
are very rare and easily lost. Forest fragmentation can therefore result in the endangerment or
extinction of interior species.
RIPARIAN VEGETATION
Riparian vegetation, the vegetation along the edge of a stream, influences the condition of both the
stream bank and water quality. Forested riparian zones are a natural part of the heal.hy ecosystems.
They provide an effective barrier and filter to runoff of water pollutants such as excess fertilizer, and
support a variety of valuable plant and wildlife species. When forests are removed right up to the
edge of a stream, the riparian zone not only loses its natural buffering capacity but also now becomes
a potential source of pollution, such as solids from soil erosion, and excess fertilizer.
Legend / % stream length
adjacent to forests
¦
More than 89.9
¦
84.6 to 89.9
~
76.8 to 84.6
~
70.6 to 76.8
¦
Less than 70.6
Forested riparian zones in Region III waterhseds
Ths Forest Health Monitoring Program (FHM), a MAIA partner, has the lead for monitoring forests
in the mid-Atlantic. The Chesapeake Bay Program is actively involved in the planting of riparian
forest buffers.
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4
URBAN SPRAWL
Urban Sprawl is low density, automobile dependent development outside of urban centers. It is wide-
spread in the U.S. and its effects impact the quality of life in every region of America, from large
cities to small towns. Urban sprawl can be measured using the U-Index (Human Use Index). The U-
Index is a measure of the total watershed area that is covered by either urban or agricultural lands.
Population growth is the most significant factor effecting urban sprawl in the Mid-Atlantic region: as
population increases, so does the amount of land required for residential and commercial needs.
Legend/% change
I Less than -1
8 -1 to 3
3 to 18
18 to 38
More than 38
~
Population Change in EPA Region III (1970 - 1990)
Areas most greatly affected by Urban Sprawl
In the Chesapeake Basin alone, between the years of 1950-1980, the percent of land used for
residential and commercial purposes increased nearly 180% while population increased about 50%.
Based upon current trends in Maryland, in a recent six-month period, approximately 5,000 people left
Baltimore City; 3,000 septic permits were issued; and nearly 10,000 acres of forests and farmlands
were lost. If these trends continue, Maryland could use as much land for development in the next 25
years as it has used in the entire history of the state. Likewise, in northern Virginia, development is
expanding beyond the current service areas of public water supplies provided by the Potomac River.
Specifically, northern Virginia's Loudon County's population has increased by nearly 150 percent
from 57,000 in 1980 to nearly 140,000 today, with the landscape changing from rural to suburban.
There are a number of environmental concerns that arise from urban sprawl. Increased human use
places greater stress on the regions natural resources. Some of the resources in the region that are
greatly affected by urban sprawl include freshwater streams, estuaries, forests, ground water and air.
population (1970 -1990)
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5
Estuaries
The estuaries of the mid-Atlantic region are generally adjacent to growing metropolitan areas such as
Baltimore, D.C, Norfolk, and Philadelphia. These areas have a high volume of storm water runoff,
which is high in pollution and effects the condition of the neighboring estuaries. The main pollutants
that affect the region's estuaries are excess nutrients, which are common in storm water runoff, and
contaminated sediments. These pollutants have adverse effects on various aspects of the estuarine
ecosystem such as the level of dissolved oxygen, the benthic community and submerged aquatic
vegetation.
The figure below shows the levels of dissolved nitrogen and phosphorous measured during the
summer months in surface waters. The main source of these pollutants is excess fertilizer runoff from
farms. It can be seen below that nutrient levels are higher than optimum in most rivers and upper
bays.
Concentrations of dissolved nitrogen and phosphorous in estuarine waters
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6
The figure below shows the distribution of summertime dissolved oxygen within one meter of bottom
sediments across estuarine waters. Dissolved oxygen is a major requirement for the maintenance of
balanced levels of fish and other aquatic biota. Reduced levels of dissolved oxygen are a result of
excess nutrients in the estuarine waters. These nutrients fuel the growth of phytoplankton, the
decomposition of which consumes oxygen. It can be seen below that the Chesapeake Bay has the
worst case of low dissolved oxygen levels
Delaware River
Dissolved Oxygen Conditions
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7
Freshwater Streams
Current patterns of suburban development have caused significant impacts to the Region's streams.
If urban sprawl continues to consume forests and farmlands in the same manner as the past, the
Region's streams will continue to degrade in years to come. The health of the Region's streams is
largely influenced by the amount of impervious cover - asphalt, concrete and other man-made
surfaces which are impermeable to rain water. Development is characterized by the conversion of
land cover from pervious to impervious. In the recent EPA/Maryland streams study, when watershed
imperviousness exceeds 2%, brook trout, which are pollution sensitive, are no longer found. When
watershed imperviousness exceeds 15%, the index of biotic integrity, which uses fish and benthic
organisms as an indicator of stream quality, is never good (i.e., fair or poor in all cases), and when
imperviousness exceeds 25% only hardy reptiles and amphibians remain.
Aquatic life is strongly impacted by increases in impervious land cover
Urban sprawl also affects the physical habitat of fresh water streams in the region. In general
good stream habitats have wide, naturally vegetated riparian buffers, meandering channels
with stable, naturally vegetated banks, and a variety of substrates such as wood, roots and
rocks. In urban areas streams are being impacted in terms of water quality, habitat, and
aquatic species. The riparian zones of many of the Region's freshwater streams have been
altered due to urbanization. In Maryland study, more than one-quarter (27%) of all stream
miles in the state are unbuffered and 14% are buffered by vegetation other than forests such as
abandoned croplands or lawns.
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In areas where forested lands are converted to urban land, many streams are channelized to
drain farm fields or to allow for the rapid removal of storm water from developed land
surface. In Maryland channelization causes the most severe physical habitat degradation on
streams. During channelization naturally meandering streams are straightened, riparian
vegetation is cut, and streamside vegetation is removed. Channelization also increases the
speed at which nutrients and sediment flush from upland streams to downstream rivers and
into the bays. About 17% of all stream miles in Maryland are channelized.
Channelization prevalent in heavily urbanized part of Maryland
'% Stream Miles
Studies of Effects of Urbanization on Aquatic Systems
The following matrix summarizes key findings from aquatic impact studies cn stream habitat
and biota. The findings point to the severe impacts on aquatic species from impervious cover
and are useful for indicator development.
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9
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Lociatipt$:y: I
Aquatic insects
Negative relationship between number of insect
species and urbaniztion in 21 streams.
Banke, et al.
1981
Atlanta
Aquatic habitat
There is a decrease in the quantity of large woody
debris (LWD) found in urban streams at around 10%
impervious cover.
Booth, et al.
1996
Washington
Fish, habitat &
channel stability
Channel stability and fish habitat quality declined
rapidly after 10% impervious area.
Booth
1991
Seattle
Fish, habitat
As watershed population density increased, there
was a negative impact on urban fish and habitat
Couch, et al.
1997
Atlanta
Aquatic insects
and fish
A comparison of three stream types found urban
streams had lowest diversity and richness
Crawford &
Lenat
1989
North Carolina
Stream temperature
Stream temperature increased directly with
subwatershed impervious cover.
Galli
1991
Maryland
Aquatic insects
A significant decline in various indicators of wetland
aquatic macroinvertebrate community health was
observed as impervious cover increased to levels of
8-9%
Hicks &
Larson
1997
Connecticut
Insects, fish, habitat,
water quality, riparian
zone
Steepest decline of biological functioning after 6%
imperviousness. There was a steady decline, with
approx 50% of initial biotic integrity at 45%
impervious area.
Homer, et al.
1996
Puget Sound
Washington
Aquatic insects and Fish
Unable to show improvements at 8 sites
downstream of BMPs as compared to reference
conditions.
Jones, et al.
1996
Northern
Virginia
Aquatic insects
Urban streams had sharply lower insect diversity
with human population above 4/acre. (About 10%)
Jones &
Clark
1987
Northern
Virginia
Aquatic insects & fish
Macroinvertebrate and fish diversity decline
significantly beyond 10-12% impervious area.
Klein
1979
Maryland
Aquatic insects
Drop in insect taxa from 13 to 4 noted in urban
streams.
Gone and
Mcintosh
1986
New Jersey
Fish spawning
Resident and anadromous fish eggs & larvae
declined in 16 streams with > 10% impervious area.
Limburg &
Schmidt
1990
New York
Fish
Shift from less tolerant coho salmon to more tolerant
cutthroat trout pop.-between 10-15% impervious area
at 9 sites.
Luchetti &
Fuersteburg
1993
Seattle
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10
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Stream channel stability
Uitan stream channels often enlarge their cross-
sectional area by a factor of 2 to 5. Enlargement
begins at relatively low levels of impervious cover.
MacRae
1996
British Columbia
Aquatic insects
& stream habitat
No significant difference in biological and physical
metrics for 8 BMP sites versus 31 sites without BMPs
(with varying impervious area).
Maxted and
Shaver
1996
Delaware
Insects, fish,
habitat, water
quality riparian
zone
Physical and biological stream indicators declined
most rapidly during the initial phase of the
urbanization process as the percentage of total
impervious area exceeded the 5-10% range.
May, et al.
1997
Washington
Aquatic insects
and fish
There was significant decline in the diversity of
aquatic insects and fish at 10% impervious cover.
MWCOG
1992
Washington
Aquatic insects
As watershed development levels increased, the
macroinvertebrate community diversity decreased.
Richards, et
al.
1993
Minnesota
Aquatic insects
Biotic integrity decreases with increasing
urbanization in study involving 209 sites, with a
sharp decline at 10%. Riparian condition helps
mitigate effects.
Steedmen
1988
Ontario
Wetland plants
amphibians
Mean annual water fluctuation inversely correlated
to plant & amphibian density in urban wetlands.
Declines noted beyond 10% impervious area.
Taylor
1993
Seattle
Wetland water
quality
There is a significant increase in water level
fluctuation, conductivity, fecal coliform bacteria and
total phosphorus in urban wetlands as impervious
cover exceeds 3.5%.
Taylor, et al.
1995
Washington
Sediment loads
About 2/3 of sediment delivered into urban streams
comes from channel erosion.
Trimble
1997
California
Water quality- pollutant
concentration
Annual P, N, COD, & metal loads increased in direct
proportion with increasing impervious area.
US EPA
1983
National
Fish
As watershed development increased to about 10%,
fish communities simplified to more habitat and
trophic generalists.
Weaver
1991
Vrginia
Aquatic insects
& fish
All 40 urban sites sampled had fair to very poor
index of biotic integrity (IBI) scores, compared to
undeveloped reference sites.
Yoder
1991
Ohio
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11
Special Issues
Impervious Surfaces and Ground Water
Ground Water is a resource of utmost importance for support of ecosystems, stream and river systems,
drinking water supplies and industrial uses. Ecologic importance of ground water includes maintaining
base flow of streams, supporting biotic communities at the interface with surface water, maintaining
wetlands and providing aquifer storage.
Impervious surfaces permanently block recharge to ground water through the soil and rock strata that
has been covered over. Impervious surfaces create conditions which result in severe drought/flood
cycles. This happens because impervious surfaces block normal recharge of ground water during rain
events resulting in decreased ground water levels. Instead of recharging the water table, the rain is
diverted rapidly to streams and may produce scouring of stream beds and organisms. When drought
conditions exist, they are severely exascerbated by the inability of the ground water supply to maintain
adequate base flow in the stream due to inadequate recharge. These conditions severely stress aquatic
organisms, habitats and vegetation. Lastly, impervious surfaces change the well contribution,
sometimes pulling contaminants from more distant areas. Changing of existing pathways of runoff by
the use of stormwater collection systems can create or exacerbate sinkhole formation in karst/limestone
geologic settings.
Drinking water protection programs, such as EPA's wellhead protection and source water assessment
programs can be a tool to help manage stormwater runoff and are an obvious opportunity for program
coordination
MS4s and Construction Activities
Proper management of storm water runoff requires multi-media efforts. Storm water falls on superfund
sites, RCRA sites, picks up atmoshperic pollutants, may cause flooding, erosion, sedimentation,
turbidity, impacts fish & wildlife habitat, impacts finfish & shellfish harvesting, boat navigation,
recharges ground water tables, and recharges surface water intakes. In the MS4 Program, EPA has the
ability to require implementation of low impact development (LID) plans in targeted growth areas.
LIDs are especially needed in developing areas because their implementation can avoid degradation of
stream quality. By using LIDs, a variety of enviornmental objectives can be achieved. The main
objectives are:
Reduce Stream Velocities - overland flow will be reduced, thus reducing stream velocities and the
resulting scouring during rain events.
Mitigate Flooding Damage - overland flow reductions reduce stream flow volume and potential for
flooding.
Stabilize Water Column - Increased infiltration will increase base flow of receiving streams. Without
proper base flow, the habitat does not provide a stabile environment for aquatic life support.
Maintain Natural Organic Matter (NOM) Levels - NOM, decreases bio-availablity of toxics and
increases acidity.
Maintain Water Supply - Increased infiltration also provides for more recharge to ground water (which
may be used for well supplies) and increases base flow, which provides a more stable water supply for
surface water intakes (volume is more consistent and salt water intrusion is prevented).
For these reasons, the storm water managment component of the MS4 permits should contain LID
requirements for targeted growth areas.
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Storm Water Sources, Impacts and Applicable Regulations
The table on the next two pages provides the linkage between sources of storm water, associated
pollutants, impacts to habitat and biota, and the associated regulatory programs. It details the
environmental damage caused by improper storm water management.
The first column identifies the major categories of activities (alterations of the natural land surfaces)
which result in damage to the aquatic environment. The second column identifies physical and/or
chemical effects which result form these activities. The third column provides details of how these
effects result in damage to aquatic organisms and their habitat. The last column identifies the regulatory
programs which are believed to have the capacity to properly manage the respective activities to prevent
environmental damage.
This table is useful for a number of purposes:
- as a baseline for review of existing impacts and applicable regulations to assess the adequacy of the
regulatory authority in abating those impacts;
- as a source for developing environmental indicators that adequately link program activities with
environmental outcomes;
- and as a source for developing an increased understanding of storm water impacts and emerging
areas of concern, particularly natural organic matter and scouring.
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13
StormWaterStoui^
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Construction
Additional Runoff
Due to Lack of
Vegetation (Bio-
retention Is Severely
Reduced)
Increased Erosion at Construction Sites and in Receiving
Water
Local E&S
State Regs
EPA Permit & Guidance
TSS/TDS
Abrasiveness Damages Plants, Finfish & Other Aquatic
Organisms, Etc (Food Supply for Finfish)
Sediments bury Plant Shoots and Fill Habitat Areas on Stream
Bed
Turbidity
Blocks Sunlight Necessary for growth of aquatic organisms
Oil & Grease
Impairs habitat, aquatic life and wildlife.
Forest
Harvesting/
Farming/Spills
Same As
"Construction"
Same As "Construction"
NPS
TMDLs
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14
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^Eolln^ants^^^^
RegMatoi!y?PpogFarasl|S
Sr'i£ffi4 W-
Imperviousness
Stream Velocity &
Hydraulics
Scouring
MS4 Permit
NPS Grants
Local Zoning
Local E&S
State Regs
EPA Permit & Guidance
TMDLs
Erosion/damage to Physical Structure of Stream Bed and
Stream Bank - Habitat Does Not Support SAVs
Damage to Hydrology Reduces Habitat (Reduced Base Flow)
Which Creates Additional Stress on Aquatic Organisms,
Reduces Population.
Reduction of
Natural Organic
Matter (NOM)
Needed for sustainability of aquatic life (NOM provides food
for small aquatic organisms and reduces bioavailability of
toxics in the water column & in sediment.)
Increases Pollutants
in Runoff
Urban/Commercial/Industrial Activities & Atmospheric
Deposition place pollutants on impervious surfaces which
mobilize more easily than on vegetated surfaces.
Flooding and
Recharge
When vegetation is removed and replaced with impervious
surface, rainfall cannot infiltrate and recharge groundwater
supplies. As the % imperviousness in a drainage area increases,
the potential for flooding increases. Flooding is a threat to
safety and can damage property.
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15
Water Quality Assessments:
Results and Analysis
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16
Stormwater Runoff is a Major Source of Urban
Stream Impairment in EPA Region III
Second Leading Source
lent in EPA Region ill
UNKNOWN
f 3599
RESOURCE EXTRACTION
5056
STORMWATER
5265 :
L SILVICULTURE
2368
HABITAT CHANGES
1561
1
AGRICULTURE
5913
Map shows land cover along with storm water-
impacted streams from TMDL list
TDML Streams Impacted by Stormwater
Runoff -from-
A/ STORM SEWERS
A/ NONPGINT SOURCES
COMBINED SEWER OVERFLOW
CONSTRUCTION
Land Cover
Urban
Fnrp-^t
] Agriculture
MBi BrastAVtjlldi id^
I Winter
~~r."
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Water Quality Assessments - Storm Water
305b 1996
DC
DE
MD
PA
VA
WV
COLLECTION SYSTB/I FAILURE
2.8
HIGHWAY MAINTENANCE AND RUNOFF
1.2
149.36
COMBINED SEWER OVERFLOW
12.3
15.9
32.1
39.38
729.58
CONSTRUCTION
1.3
5.1
129.2
60.9
1276.86
URBAN RUNOFF/STORM SEWERS
36.6
147.5
372.2
887.42
1365.27
Total
51.4
168.5
501.4
93
926.8
3523.87
305b1998
DC
DE
MD
PA
VA
WV
URBAN RUNOFF/STORM SEWERS
38.1
124.65
398.84
320.42
1189.73
CONSTRUCTION
1.6
5.1
143.75
1072.83
COMBINED SEWER OVERFLOW
12.3
7.9
17.11
32.23
514.1
HIGHWAY MAINTENANCE AND RUNOFF
167.14
COLLECTION SYSTEM FAILURE fSSO)
1
23.96
6.25
Total
52
137.65
1
559.7
376.61
2950.05
305b 2000
DC
DE
MD
PA
VA
WV
URBAN RUNOFF/STORM SEWBRS
38.4
304
605
1000
719
254
COMBINED SEWER OVERFLOW
12.3
224
RAW SEWAGE
297
Total
50.7
304
829
1000
719
551
TMDL1998
DC
DE
MD
PA
VA
WV
URBAN RUNOFF/STORM SEWfflS
457.76
535.57
CONSTRUCTION
142.18
COMBINED SEWER OVERFLOW
12.3
33.73
58.68
Total
12.3
0
633.67
594.25
0
* all values are stream miles
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18
The chart shows typical storm water categories used in 305b assessments.
STORM WATER CATEGORIES
URBAN RUNOFF/STORM
SEWERS
CONSTRUCTION
COMBINED SEWER
OVERFLOW
HIGHWAY MAINTENANCE
AND RUNOFF
COLLECTION SYSTEM
FAILURE
0 500 1000 1500 2000 2500 3000
Data is from the '96 305b assessment. miles impacted
§q|g||§jj|
wmmmm
I I |
psc £ S8 ^ ; - .cy 'v
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19
Analysis of Water Quality Assessments
Based on a review of the past 6 years of state water quality assessment data, storm water runoff is the
second leading source of stream impairment in EPA Region HI. This refers to all storm water
categories: urban runoff, storm sewers, CSOs, construction, highway runoff, and collection system
failure. Storm water impacts are most prevalent in urban areas.
Over 5000 stream miles have been identified as impaired from stormwater runoff, but only about 1700
of those stream miles are on the TMDL streams list. This is because there are a number of reporting
consistency issues with the assessments. Another concern that many lower order streams are not even
assessed for storm water impacts. There is no consistent set of parameters which must be assessed in
the 305b analysis and there is no matrix of parameters assessed/not-assessed which is available with
the streams. Therefore, one cannot tell by looking at an assessment what parameters were measured
and more importantly what parameters were not measured. This should be a requirement for 305b
reporting.
Data standards are key to evaluating water quality impairments and making comparisons and trend
analyses. In the TMDL list some states use "nonpoint sources" as a source category without
identifying the specific contributing nonpoint source categories. In the 305b assessments, "nonpoint
sources" is not used, rather specific nonpoint sources are identified by states. This issue makes
comparisons between the 305b assessment and the TMDL listings very difficult. Also, the unique
stream identification system called Stream Reach Indexing is not used by states in developing water
quality assessments or TMDL lists. Again this makes data analysis, especially geospatial analysis
difficult when working with 305b and TMDL data together. States should report the EPA Reach File 3
identifier for all stream water quality listings. Continued focus on improving consistency in reporting
standards is important for correctly assessing the problem extent and measuring progress.
Another issue is the elecronic reporting and updating of water quality assessment data and maintenance
of geospatial data layers in the spatial data library. This process needs to be streamlined and to address
the issues identified above - data standards, 305b-TMDL consistency, RF3 indexing - in order to have
good quality, up-to-date assessment data from which to base decisions and evaluate progress.
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20
Chesapeake Bay Characterization
The data presented in the Chesapeake Bay characterization provides a foundation of key metrics which
are necessary for modeling and predicting future growth and associated changes to land cover,
impervious cover, pollutant loads and impacts to aquatic life and habitat.
Population Growth Projections
Expected Population Change by County,
1980-2020
Population Change
-34 - 0
¦ 1-35
IBS 36 - 70
71 -105
106-140
140 - 259
Counties with Highest Expected
Population Growth (by State)
Watershed-wide, the population is projected to increase by 2.2 million people from now until 2020
(from 15.59 million to 17.76 million).
Left map: Census bureau projected population growth from 1980 to 2020, based on 1990 census data.
Right map: Indicates the counties in MD and VA that are expected to double in population by 2020;
and the counties in PA that are expected to increase population by 52% by 2020.
Population is increasing throughout the watershed. With increased population comes increased
impervious surfaces (roads, buildings, parking lots). Planning for and controlling additional urban
stormwater runoff and pollutant loads will be very important.
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21
Land
Landuse is based on 1990 EMAP data (satellite imagery) projected to 2000 using population growth
and the census of agriculture.
Pollutant Loads
Nitrogen sources to the Chesapeake Bay
Direct
Mixed Forest
6% 14%
Land Use in the Chesapeake Bay Watershed
Agriculture
23%
Urban makes up 9%
of land use
Water
1 %
Mixed
10%
Forest
57%
Urban
9%
Cities contribute to the Bay about twice the nitrogen and phosphorus load per acre as agriculture.
Urban land use is responsible for 12% of total nitrogen loads to the tidal Chesapeake Bay (even though
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22
it makes up only 9% of the watershed landuse). About 90% of atmospheric contribution of nutrient
loads is thought to come from anthropogenic sources such as vehicle exhaust, power plants, and
ammonia from agriculture.
Phosphorus sources to the tidal Chesapeake Bay
Urban makes up 15%
of phusphnm loads.
Agriculture
44%
Urban
15%
Mixed
10%
Forest
2%
Direct
Deposition
8%
Point Source
21%
Urban land use is responsible for 21% of total phosphorus loads to the tidal Chesapeake Bay. If you
look at just the nonpont sources of nitrogen, urban land use is responsible for 27% of phosphorus
loads.
TSS Sources to the tidal Chesapeake Bay
Agriculture
63%
Urban makes sip 9%
of TSS loads,
fumfcrestinjated
range is 2.5-32%-)
Forest
20%
Mixed
8%
U rban
9%
Urban land use is responsible for 9% of total TSS loads to the tidal Chesapeake Bay. Urban land use is
responsible for 9% of TSS loads, but this estimate does not fully account for TSS resulting from stream
bank erosion and scouring of streambed that may be due to increased stormwater flow resulting from
urbanization. Thus a more thorough estimate of urban contribution to TSS loads is 25-32%.
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23
Areas of Concern
Northeast
1 j>Elk
Chester
¦Eastern Bay
,Wye
_,Miles
jjthoptank
South (
Rhod'
Patuxent
Elizabeth
Susquehanna1
Bush.
Gunpowder x-
Middle.^
Baltimore Harbor/Patapsco
Magothy^
Anacostia®,
Potomac
Rappahannock
MattaponlQ
PamunkeyOv.
Chickahominy _
\York
Bohemia
Sassafrass
James
Status of Chemical Contaminant
Effects on Living Resources
in the Chesapeake Bay's Tidal Rivers
Nanticoke
Manokin
Big Annemessex
O Pocomoke
Tangier Sound
LEGEND
~ Region of Concern -
area wth probable
adverse effects
3 Area cf Emphasis -
area with potential for
averse effects
Area with Low Probability
for Adverse Effects
~ Area wth Insi/ficient or
Inconclusive Data
rNot characterised due to
historically low levels of
chemical contaminants
This map indicates the status of chemical contaminant effects on living resources in the tidal rivers of
the Chesapeake Bay.
LEGEND:
RED - Regions of Concern with known toxics problems.
YELLOW - Areas of Emphasis with the significant potential for adverse effects
GREEN - Areas with Low Probability for Adverse Effects
WHITE - Areas with Insufficient or Inconclusive Data
The CBP is currently targeting assessments in these areas to complete this characterization. The CBP
has developed a list of chemicals of concern in each of the red and yellow areas.
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24
TARGET WATERSHEDS - TOXICS
JAMES - metals
ANACOSTIA
ELIZABETH RIVER
BALTIMORE
HARBOR
PATUXENT
pesticides, metals
POTOMAC
PCBs, PAHs,
Pesticides, metals
Question: Do the chemicals of concern come from urban stormwater runoff? Or are point sources the
bigger problem? Chemicals of concern can come from both point and nonpoint sources. Sometimes
point sources dominant and sometimes urban stormwater runoff is the dominant source.
The target watersheds above are those watersheds that have a substantial urban stormwater
contribution of chemicals of concern.
These Regions of Concern are most known for their sediments contaminated with historic/legacy
chemicals that are no longer in use or have been banned, however, urban stormwater loads can be
significant. The Chesapeake Executive Council committed in the Toxics 2000 Strategy to reduce the
chemicals of concern in the Regions of Concern by 30% by 2010.
Note: Cities contribute about twice as much nitrogen and phosphorous on an acre-by-acre basis as
agriculture.
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25
Indicator Development
Environmental indicators should be developed in order to more effectively monitor administrative
actions and results along a range of levels from facility actions to ambient stream measures to indices
of biotic intergity. By developing such indicators, the linkages between all these varied levels of
action are explicitly identified and so it becomes much easier to guage progress and effectiveness.
The following chart shows a basic indicator framework for the storm water issue. Much of the
research discussed earlier in the report shows a number of sensitive measures, such as percent
impervious area, which have strong linkages to high level ecological health outcomes. This research
provides a rich resource for developing a suite of indicators with which we can sensitively guage real
environmental progress through a number of levels. Having strong linkages between intermediate
environmental measures and high level health outcomes will enable the identification of significant
progress at a much earlier time frame than would be possible if only the end result were measured.
Storm Water Hierarchy of Indicators
• Fish/benthic Indices
Riparian buffers
Stream flows during storm event
• Ambient pollutant levels:
TSS, metals, pathogens, nutrients
Impervious Surface Measures
Pollutant loading reductions
Community/Developer Changes:
LIDs, BMPs
Permitting, Enforcement and
Outreach/Education
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26
Targeting Areas for Enforcement and Outreach
Targeting increases the effectiveness of our activities by focusing limited resources on those areas
which will benefit most or have the greatest result for our expenditures. There are a number of
approaches to targeting. One particulalry useful approach is the use of severity criteria/indicators.
Severity criteria/indicators are known quantifiable factors which can be linked to a geographic
location, such as sensitive populations or endangered species habitats. There are many geospatial data
layers associated with the storm water issue such as MS4 locations, impaired streams, and sensitive
habitat areas. A preliminary list of relevant data layers is shown below along with maps of MS4
locations for Phase I and Phase II. The first step in the targeting strategy is then to develop the spatial
analysis of these criteria and find the areas where there is the greatest concentration of severity
indicators.
Severity Criteria/Indicators
Impervious surface cover
MAIA indicators - such as forest fragmentation
Storm water impaired streams
Exceptional value waters
Population growth areas/sprawl areas
Drinking water intakes
MS4 areas
Superfund sites
RCRA sites
AFOs
Mines
Junk yards
Shellfish beds
Spawning areas
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27
Phase I Permitted MS4 Operators in EPA Region
IM
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28
Legend
ys r l^aialVaabBda,
t V CfibiB RmrfTa Swa Scwa 0JT
WV Spcndc Ebuada.o d'Tawn, voifa Ptrncll Pacu
I o'- '1WV" Caiaua widb Pfaox H Pt ou
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VA lipcnic Saiadaici a l" Tomsi wtt Pfaaic T1 paau
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PA Tn-ivnjbp wiit Phan 11 pe tau
t'-i&iiPA Coubuq wiib Ptmc H pa emu
Phase II Permitted MS4 Operators in EPA Region
& TUCb Infb TTTvStilT. •
divan to tfti foBi^t hTPict (W
Uuda W54 apsiaua a itaai<: pa anal aid itc p nraa afcfctoainjn Ptnjcl pamu
fapmai TYaa b,do, Sou oc: IMG ite[d) TWDL, CfS EPA
VibaRiariT a Smim Scwrj Ctalf
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29
Conclusion and Recommendations
This report has outlined the numerous environmental issues and concerns related to storm water and
the sources of storm water including the drivers of population growth and development. Key findings
from studies revealing the widespread environmental effects of storm water on habitat and organisms
have been presented. The extent of streams identified as impaired in the Region has also been
described.
The overall conclusion is that storm water is part of a pervasive and environmentally harmful pattern
of development which involves the construction of large areas impenetrable by rainfall: impervious
areas. Impervious cover has numerous harmful effects on such diverse conditions as stream flow,
aquatic organisms (from insects to finfish), ground water recharge, erosion, and stream scouring.
Sensitive organisms in particular are particularly sensitive to impervious cover and are no longer
present after such cover reaches even a low percentage of the upstream watershed.
The following are the specific recommendations with suggested leads. All of the recommendations
have short-term and long-term components.
Make state 305(b) and 303(d) reports/lists consistent Region-wide and more comprehensive:
* Develop data standards for reporting.
* Develop a consistent data flow process for updating the regional databases and GIS
coverages.
* Develop a standard assessment matrix of monitored parameters which will be used in each
stream assessment.
SUGGESTED LEAD: WPD with ESD, GIS Team and OED
Use innovative impervious surface models as well as MAIA landscape indicators to predict the most
sensitive areas which have the greatest potential for degradation from storm water runoff over the next
5 years. Use modeling to identify steps to prevent degradation.
SUGGESTED LEAD: WPD, CBPO, OED and GIS Team
Identify the most sensitive/valuable areas that are presently degraded and would benefit the most by
improving the management of storm water runoff. Identify steps to mitigate degradation.
SUGGESTED LEAD: WPD, CBPO, GIS Team and OED
Develop environmental indicators to sensitively measure storm water impacts and progress from
abatement efforts.
SUGGESTED LEAD: OED, CBPO, WPD, with GIS Team Support
Provide comments on the SW general permit for construction activities which require permittees to
address known concerns about the creation of impervious surface areas, to use LID strategies and to
use newer BMP control strategies.
SUGGESTED LEAD: WPD
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DATA SUBGROUP MEMBERS
Richard Paiste, OED, Chair
Carmine Constantine GIS Team (Contractor)
Kelly Eisenman (CBPO)
Don Evans, GIS Team (OPM)
Dale Long, WPD
Chuck Schadel, WPD
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