,STANDARDIZED PROCEDURES FOR PLANTING VEGETATION^
i"~" ON COMPLETED SANITARY LANDFILLS
3-1/8'
__ __ 1_ __ ,;_-]
Edward F. Gilman
,„., Franklin B. Flower
Ida A. Leone
Rutgers University
New Brunswick, New Jersey 08903
l
Grant No. CR807673
Project Officer
i Robert E. Landreth
'• Solid and Hazardous Waste Research Division
j Municipal Environmental Research Laboratory
Cincinnati, Ohio 45268
MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT'
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268 . . -
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A
DISCLAIMER
! The information in this document has been funded wholly or in part by
i the United States Environmental Protection Agency under assistance agreement
I number CR807673 to Rutgers University. It has been subject to the Agency's
i peer and administrative review, and it has been approved for publication as
i an EPA document. Mention of trade names or commercial products does not
constitute endorsement or recommendation for use.
ii
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FOREWORD
The U.S. Environmental Protection Agency was created because of
increasing public and government concern about the dangers of pollution to j
the health and welfare of the American people. Noxious air, foul water, and
spoiled land are tragic testimonies to the deterioration of our natural
environment, the complexity of that environment and the interplay of its
components require a concentrated and integrated attack on the the problem.
Research and development is that necessary first step in problem
solution, and it involves defining the problem, measuring its impact, and
searching for solutions. The Municipal Environmental Research Laboratory
e
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NS
Ht.RE
ABSTRACT
A manual was developed for those charged with establishing a vegetative
cover on completed landfills. Special problems associated with growing
plants on these sites are discussed, and step-by-step procedures are given
for converting a closed landfill to a variety of end uses requiring a
vegetative cover. Instructions are given for vegetating landfills with
either limited or adequate funds. A hypothetical case of landfill
conversion is also included.
This report was submitted in fulfillment of Grant No. CR-807673 by
Rutgers University under the sponsorship of the U.S. Enviromental Protection
^Agency.—This-ireport1 covers-the-period-August-1980 to July"1982,~and work -^
was completed as of July 1982. j i
9-1/8"
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' !
i
!
JS|—
"3^
CONTENTS
i
Foreword ...
Abstract . . .i
Figures. . . .j
Tables . . . .'
Acknowledgment
I
1. Introduction j
2. Vegetating Landfills with Limited Funds
Selecting an end use
Determining depth of cover. .. ..
Establishing~an~erosion-control- program-.—7 —
Determining the soil nutrient status
Determining soil bulk density
Amending cover soil
Selecting landfill-tolerant species
Planting grass and ground covers
Developing tree and shrub growth
Vegetating Landfills with Adequate Funds
Step B-l: Contructing the landfill
Extracting gas
Selecting gas barriers
Selecting cover soil
Spreading cover soil
Soil depth. :
Locating areas unsuited for tree and shrub
growth.
Selecting tree and shrub material
Planting and maintaining vegetation
Step A-l
Step A-2
Step 'A-3
Step A-4
Step A-5
Step A-6
Step A-7
9'1Step A-8
Step A-9
3.
Step B-2:
Step B-3:
Step B-4:
Step B-5:
Step B-6:
Step B-7:
"Step B-8:
Step B-9:
4. Landfill Conversion: A Hypothetical Case
References
v
vi
vii
viii.
!
i
1
2
2
2.
— 3-4
9
10
10
10
11
- 12
13
13
14
15
16
19
20
22
24
32
35
37
5PA-237
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CHOPPED
HEAD.
3EG1M
FIGURES
j Number i I Paee
, —^_«___ j •*• c*&g*
j 1 Suggested grid pattern for sampling soil depth on a
i 50-acre site , 3
i ' I
i i
2 Experimental design plan for testing tolerance of
grass species to landfill. .1 .5
-3- —
Gas -protection scheme using -synthetic-membrane-covering • —
large areas of former refuse 15
i !
Good tree and grass growth in 75-cm soil mound over a
3-cm thick layer of bentonite 17
i- i/ 0
5 Gas prevention scheme for small planters 17
! i
6 Gas prevention scheme for vegetation planting island in a
paved parking lot over a former refuse landfill 18
! i
7 Area with shallow cover soil and consequently little or
no plant growth 22
1 i
8 Excavated green ash on landfill showing most roots in top
soil layer 28
~! - '
9 Excavated green ash in control area showing even distribution
of root system.............;................„....... „..... „. 29
3'8"
c?A-i2? O;;i.
• 1-751
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3EG": j
TABLES
Number
Page
Some grasses and legumes that should be tested
for landfill adaptability
...5
,6-7
2 Suggested herbaceous species for erosion control
1 i
—3 — Preferred:varieties of seed -for- erosion-control -on
Pennsylvania landfills.. I 8
Some'slow, moderate, and rapid growing tree species
found in the United States
9-1/8" |
t '
Volunteer (pioneer) species indigenous to various
geographical areas of the United States
6
7
Vertical distribution of tree roots in landfill and
non-landfill soil '.
Some small trees and shrubs (less than 9 m tall
at maturity) ;
,25
,26
.27
,31
* 3/8'
'Gin.
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A
CROPPED
SECTIONS
r
SECTION 1
INTRODUCTION
Completed landfills throughout the United States are being developed
into parks, golf courses, nature areas, and other multiple-use facilities.
A critical factor in achieving one of these end uses is establishing and
maintaining an effective vegetative stand on the final cover soil. This
manual is written for those charged with establishing such a cover. The
special problems of growing plants on completed landfills are discussed, and
step-by-step procedures are given for converting a closed landfill to a
variety of end'uses that require a vegetative cover.
The manual;has three major sections: Vegetating a completed landfill j
with limited funds, vegetating a completed landfill with adequate funds, and
converting a hypothetical landfill to a multiple-use recreational facility 1
with adequate funds. I
9-1/8"
! 1
Each section presents a series of steps to be performed in sequence.
Data were collected from more than 60 visits to landfills in 21 states
(Flower et al., 1981 and Leone et al.', 1979), other experiences in the
field, textbooks, and standard references on the growth of plants under
adverse conditions. j
i
£:jA-237 ;c,n.
1-+-/01
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DnOPPSD i
HEAD, j
nr.-'M i
O£OUV i
SECTIONS;
H5?E 13
SECTION 2
VEGETATING LANDFILLS WITH LIMITED FUNDS
STEP A-l. SELECTING AN END USE
i
The process of selecting an end. use for a particular landfill will be
largely dictated by local needs and the politcal community. The selection
should take place as soon as possible to expedite initiation of all steps
required to complete the project. Accomplishing each step will be much
easier once a plan has.,been formulated. In cases_where_funds_ are_limited,
the "plan mTghlE include a passive park, a hunting ground, or a natural
open space where trees, shrubs, and grasses will be planted. (Golf
courses, multiple-use parks, and other highly intensive recreational
uses would require greater expenditures and will be covered in Section 2 )
If an end use has not been selected, then controlling erosion will be the
primary short-term goal (see Step A-3).
1 '
STEP A-2. DETERMINING DEPTH OF COVER
i i
Probably because of high costs and lack of availability, the amount
and quality of soil covering the refuse in a landfill has frequently been
found to be inadequate for vegetation growth. Such deficiencies need to
be corrected before grass or woody vegetation is planted. The cost of
covering an entire landfill with enough rich soil for satisfactory tree
growth is excessive. Therefore, enough soil should be present to bring
the total depth to 60 cm (not including the gas barrier layer) in all
areas except where trees and shrubs will be planted; the latter areas
require at least 90 cm. If portions of the landfill have no cover soil
over the final refuse layer, select and spread soil according to steps
B-4 and B-5. j i
' i
A back-hoe is best suited for determining soil depth, because many
holes can be dug in a short time. If this equipment is unavailable, a
soil auger and shovel can be used. Because soil depth generally varies
over the landfill, several determinations should be made at different
points in the'area to be planted (Fig. 1).
50TTC
IMAGE
CUTS!
•^ 3/8" ---,
1 L
5A-;37 (Cm.)
TrATH
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UMw'i ~r!_'
HEAD
s»-
90
'•90
90
*
70
•
70
i
i
90
f
— 90
1
ds
1
i
60
*
)
80
f
85
— 90
80
•
50
80
90
"'"90 "
70
40
90
8?.
• 80
70
20
80
*
85
/b
*
20
20
80
85
•~75~~
20
10
*
40
90
" 70
*
20
40
50
9p
70
30
90
80
9.0
85
45
*
90
80
•
i
1
1
i
I
Figure
9-1/3"
Suggested grid pattern for sampling soil
depth on a 50-acre site (values, in cm).
By digging a minimum of one hole per acre for large sites (>50 acres) and i
two holes per,acre for smaller areas,, enough data can be collected to make i
an adequate determination of whether additional soil is necessary, how
much is needed, and where it should be placed. Follow the procedures in
Steps B-4 and B-5 when selecting and spreading additional soil cover.
Fifty holes are dug in a grid-like pattern with a back-hoe, and soil
depth is measured in each hole and recorded on a map of the site
(Figure 1). The results show that more soil is needed in the center of
the site. Two options are available to the landscaped •. 1) soil can be moved
from the northwest end of the fill to the center, or 2) soil can be j
trucked in from another site and spread in the center. Moving the soil is j
the obvious choice if trees are not to be planted in the northwest end and j
if the soil is of good quality (see Step A-4). If the soil is poor,
however, and a stand of trees is desirable (e.g., as a source of food and
cover for wildlife), consider bringing soil of a higher quality for the
center and planting the trees there.' If the cover soil on the site is
suitable for tree growth in some areas (see Step A-4), supply soil in the
center to a depth of 60 cm for grass establishment and plant the trees
wherever there is enough soil for tree root development (i.e. 90 cm).
7
SO: K
iMAG'
CUTS
^»i
TP.AT:
i?A-237
•4-7S5
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DRC°?
r-E^O.
"STEP A-3. ESTABLISHING AN EROSION CONTROL PROGRAM —
!
Testing Tolerance of Ground Cover Species
I I
The soil on recently covered landfills must be stabilized soon after
-spreading to prevent erosion. But the combination of soil conditions —
-found-on-completed -landfills- is not found-in -other-areas.—Soil-concen
rations of C02 and CIfy can be high, and 02 can be low. The soil is
frequently of poor quality, soil moisture is often limiting, compacted
soil is common, soil temperatures can be high, and exposure to weather
can be extreme. Furthermore, little is known about grass and ground cover
adaptability to landfills, and tolerant species have not been identified.
Since no research has been published on establishing grasses on landfills,
a one-growing-season study should be conducted to select landfill-tolerant
grasses. Such studies can be easily performed during the operation of the
active portion of the landfill. About 2 acres will accommodate-, the
following experiments.
First, -select -several-closed-, areas-that-will- remain .undisturbed-Jfor
at least one growing-season if the landfill is still active. If the fill !
is above ground, five areas will be required—one on the flattened top, and
one on each of the four compass cardinal-point side-slopes of the landfill,
since species growth requirements may be specific for different exposures.
9-1/8" j
The conditions at the experimental plots must represent those expected
over most of the fill area if meaningful conclusions are to be drawn. j
Conditions that should be considered include (1) cover soil depth, type,
and compaction, (2) soil gas concentrations, (3) refuse type, depth,
age, and compaction, and (4) surface aspect and slope.
! |
Soils in the experimental plots should be tested for pH, Mg, Ca, P,
K, N03, NH4, conductivity, Cu, Fe, Zn, Mn, particle size distribution, bulk
-density, and organic matter.. Four to five samples should be collected per !
acre. Step A-4 gives the details on collecting these samples. Soil tests 'l
should be performed by the State Agricultural Experiment Station or other
certified soil testing laboratory to indicate whether amendments and/or
conditioning is required for acceptable seed germination and growth.
These amendments should be applied according to soil test recommendations
and mixed into the top 15 cm before the plot is seeded.
Each test area should be divided into at least three blocks and
each block should be planted with all the species being evaluated in 9-
to~18m2 plots delineated by string (Figure 2). This will provide three
replications 'of every species in each area. The species should be randomly
distributed within each block. Hand seeding will be necessary. Twenty i
or more species can be easily handled in this manner. !
I ! I
I SOTiC
i IMAGE
! CUTS!
7 C!M=;-,
2 3/B"
>AND
'C',',:.)
. 4-76!
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DROPPED I
HEAD.
BEGIN
X
I v_/
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1
2__
3
4
5
6
7
— 8-
9
10
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18
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-20
21
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18 -
19
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24
1
2
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<*
o
7
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9
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-12-
13
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3
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9
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16-
17
18
19
20
21
— *%rt .
2.2.
23
24
1
2
Block; 1/2*
_Block-2 Block 3
Figure 2. Experimental design plan for testing tolerance
I of grass species to landfill. Numbers in blocks
j indicate different species.
9-1/8"
Seed companies and the State Agricultural Experiment Station are
likely to cooperate in selecting species with which to experiment. In
most cases, seed varieties should be chosen to accomodate very dry sites
and the cover soil conditions particular to the landfill (these .should be
checked by testing the soil as in Step A-4), Species selection may require'
more care on fills with a known end use, since aesthetics and compatability
with the end use must be considered along with erosion control. A list j
of species that have been recommended for strip mines or other difficult-
to reclaim areas are listed- in Table 1.
TABLE 1. SOME GRASSES AND LEGUMES THAT SHOULD BE TESTED
I FOR LANDFILL ADAPTABILITY3
Grasses
Legumes
3EG:
LAG'
OF •
Kentucky 31 Festuca arandinacea
Perennial ryegrass Lolium perenne
Weeping lovegrass Eragrostis curvulara
Millet Echinochloa spp.
Reed canary Phalaris arundinacea
Switchgrass Panicum virgatum
-Orchard grass Dactylis glomerata
Crownvetch Coronilla varia
Birdsfoot trefoil Lotus corniculatus
Alfalfa Medicago sativa
Lespedeza Lespedeza spp.
Flatpea Lathyrus
aReference: Vogel, 1981
30TTC
I MAGI
GUTS
\ Dl.V.Ef
j ~CR T
EPA-237 (Cin.)
'4-761
• MBFR
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TABLE 2. SUGGESTED HERBACEOUS SPECIES FOR EROSION CONTROL
Geographic
Regions
Northeast &
North Central U.S
and Northern
Appalachia
•
Mid and southern
Appalachia,
western
Kentucky,
Arkansas,
Oklahoma
I
S ? 1 1 3
Seeding
Time
Early spring
to
mid-spring
Mid-spring
- -~ • to ~ " " '
mid-summer
Late summer
to
early fall
Early spring
to
mid-spring
Late summer
to
early fall
Temporary (quick cover annual) Permanent (L<
_j species3 i, J perennial t
(use one with permanent mix)
Name Seeding rjate Name
(Ib/acre)
Annual ryegrass
Perennial ryegrass
Oats
Weeping lovegrass
Foxtail millet
• - "Japanese millet" """
Weeping lovegrass
Rye
Winter wheat
Annual ryegrass
Perennial ryegrass
Oats
Weeping lovegrass
Annual ryegrass
Rye
Winter wheat
Annual ryegrass
Perennial ryegrass
Crimson
s"\
1
25 |
»!
10 1
1
.... . ^ i
so r
10 |
I
80 j
80 '
25 t
i
50 i
75 1
25 !
80 j
80 I
25
50 1
50 |
f
Ky-31 Tall fescue
Birdsfoot trefoil i
Crownvetch or
Flatpea
1
t
i
|
?ng lived)
species ^
Seeding rate ,
(Ib/acre)
md 75
Jr 30
50
80
Ky-31 Tall fescue and 75
Birdsfoot trefoil <
Crownvetch or
Flatpea
Ky-31 Tall fescue j
Birdsfoot trefoil <
Crownvetch
Ky-31 Tall fescue a
Korean and/or Kobe
Lespedezac or
Crownvetch
Ky-31 Tall fescue
Sericea lespedeza
(1/2 unhulled seet
Crownvetch
sr 30
50 ,
80 ;
md 75
>r 30
50
md 75
i
50 j
50
and 75
)~ or 50 i
50
r\ '
-------
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in
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>: r *~
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'.'if r"
..../r_
h;u •
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co
Geographic
Regions
Mid and
Southern
Appalachia
:'.:j:j: Illinois,
:':•: Indiana,
""* Iowa,
'••' Northern
•;: :'j: Missouri
Missouri,
Kansas,
Oklahoma
— Use only
of each
TABLE 2. (continued)
Seeding
Time
Early-spring
to
mid-spring
Early spring
to
^mid- spring
Early spring
to
mid-spring
Late summer
to
early fall
one of the temporary
species in proportion
'v ,/
1
Temporary (quick cover an
species
(use one with permanent m
^ ' _,.,..,,-. „. . ~ . —___
Name Seeding ra
(Ib/acre
Weeping lovegrass
Sorghums
Pearl millet
' Foxtail millet
Browntop millet
Oats
Annual ryegrass
Perennial ryegrass
Oats
Winter wheat
Rye
species at rates shown
to number used (i.e.,
10 *
80
50
50
.. fin
75
25
50-
75
120
120
. If more
for two spe
r
nual) Permanent (Lon
perennial sp
lx)
te Name
-? Ky-31 Tall fescue
Sericea lespedeza^
Korean and/or Kobe
Lespedeza —'
Ky-31 Tall fescue
Smooth bromegrass
Alfalfa or ' '
Birdsfoot trefoil
Crown vetch
Ky-31 Tall fescue
Alfalfa or
Crownvetch
Ky-31 Tall fescue
Alfalfa
than one is used, reduce
:cies, use half the seed:!
i
rii •
"'• :•:• :;: a 1 .'"
< ) " ,n
::< a
W ':': _ , t
'i i1
g lived )
acies
Seeding rate
(Ib/acre)
and 75
or 50
50
or . 75
and 75-
— 50—
or 30
50
:
and 75
50
50
and 75
50
seeding rate |
ing rate of each)
L.^,
Ji'Half or more ot Sericea lespeaeza seea snouia oe unnuiieu auu uusuaj
germination and insure sufficient seed for germination next spring.
I ,
S-'fhese annual lespedezas usually reseed each year and may become a permanent component c
f jthe
-1 )•> '11 .
> - <
-------
- The experiments should be planned so that seed can be sown preferably
in the fall, or where necessary, in the very early spring. The seeding rate,
which varies with the species, can be suggested by the seed supplier. Seed
companies and soil conservationists generally recommend that the seeding j
rate be several times that specified for undisturbed lands. Several
..legumes (Table 1) should be tested along with the grasses; since they 1
jLre_widely_ adaptableland_require,.far.,less_nitrogen_j£or.., growth, .-they.-.are j
often used for reclamation purposes.'' j
' ' i
Mixtures .of annual and perennial species (Table 2) are reported to be
best suited for stabilizing soil and protecting against erosion on reclaimed
strip mines. iThe annual plants provide a quick temporary cover that is
succeeded by a more permanent perennial species. Seeding rate recommend-
ations should be followed carefully for the quick-cover species, because
higher rates could produce dense stands that prevent or retard establishment
of the permanent species.
i
If it becomes necessary to cover portions of the landfill with soil-
holding grasses__before. the_experiments Jiave been_cgmpleted,_then_the
,r _, •^r-£-cuYtu^ai agent or soil conservation service can supply the
standard seeding and feeding rate (based on the soil analysis outlined in
Step A-4) for that area for the species selected from Table 1 or otherwise
recommended by the county agent. !
Mixtures"for spring and fall seeding are suggested in Table 2. Some
of the mixtures suited for erosion control and site stabilization are not
compatible with other land uses. For example, Sericea lespedeza and
flatpea are excellent for long-term erosion control, but their value as
forage and wildlife habitat is lower than that of other legume species.
Species should thus be selected for their suitability for the approved
land use as well as for their ability to control erosion. Some specific-
ations are given in Table 3 for erosion control plantings found to be
adapted to conditions on landfill sites in Pennsylvania (Swope, 1975).
i !
TABLE 3. PREFERRED VARIETIES OF SEED FOR EROSION CONTROL
ON PENNSYLVANIA LANDFILLS
i Species |
!
i Tall fescue I
Birdsfoot trefoil
Crownvetch '
Variety
K-31
Empire
Penngift
Lbs/Aere
20
4
6
PAGE .^
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DROPP
HEAD;
Planting Procedures j
i
The best procedure to prevent erosion is to microterrace steep,
sloping ground before seeding and mulching. Microterracing can be
accomplished by running a wide-tracked bulldozer up and down the slope
'—without touching the soil with the blade, to create a series of ridges —
-and -troughs-across-the-side-of-the-slope -that-will—help ~prevent~erosion—
and aid in seed germination and growth.
i !
The seed should be handspread in each subdivision and raked into the
soil. A mulch and tack designed to hold the seed in place should be
applied to sloping areas where grass seed has been planted to prevent
the seed and soil from washing out during heavy rains and to help keep
moisture in the soil. Some of the annuals can be seeded in the spring
and then cut and used as a mulch in a fall perennial planting.
•oi -i. :±:
Grass and ground-cover growth should be evaluated once a month by a
qualified specialist during the first 4 to 6 months following seed
i i
The soil' on landfills that have been covered and completed for 1 or
more years may have volunteer and planted vegetation that was placed there
before plans were developed for a specific end use. If the particular use
will include-'a?natural area, consider testing those species that are
already volunteering on the site. These are likely to. include a variety
of annual species if the site is young, or perennials if the site has been
established for 2 or more years. Begin these experiments in the fall so
that the following three steps (determining soil nutrients and bulk
density and amending the cover soil) can be implemented during the next
summer. Planting over the entire landfill can thus be done the following
fall. | j
STEP A-4. DETERMINING THE SOIL NUTRIENT STATUS
' S
Sampling Procedure j
Before or during the grass and ground cover experiments, soil tests
should be made for pH, the major nutrients (nitrogen, potassium, and
phosphorus), conductivity, bulk density, and organic matter. Where
possible, tests should be made for the other macro-and micro-nutrients
mentioned in Step A-3. Soil samples for these tests should be collected
over the entire landfill in a number of areas within the proposed planting
sites. A grid or zig-zag sample pattern should be used. If the cover
soil is homogeneous and originated from a single source then one sample
for each 5 acres may be sufficient. 1 But if a wide variety of materials
were used as cover, then a more frequent sampling pattern should be
designed. Samples should be collected from a 0 to 20-cm-deep soil column.
Five subsamples should be collected over an area and pooled to form a single
composite sample. Any of a number of soil auger types or shovels may be j
used to obtain samples (picks and shovels may be required in very compacted
soils). Decaying plant material, roots, etc. should be removed from the !
sample. ' • ;
OUTSi
'•••<: •:. 9
THAT;
SPA-237 (Cin.i
;4-75i
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!Fertilizer
!
DROPPED
HEAD;
BEGIN
SECTION;
HERE ';
EEGiM
EXi
The local county agricultural agent or soil conservation service office
may help to collect and analyze the samples, interpret the results, and make
recommendations for the addition of fertilizer and/or lime. Remember j
"however, that fertilizer may encourage such rapid, vigorous growth of |
-the -herbaceous—vegetation"thatr the~establishment~of "woody ~species~f rom |
seed may be supressed or prevented. ,' Again, such site-specific problems ]
must be worked out with local officials and reclamation specialists
i
Metals i
Soils that contain high concentrations of zinc, copper, manganese,
iron, cadmi,um, or lead should not be. used for cover material unless this
situation can be corrected by increasing the pH between 6.5 and 7.0,
increasing the phosphorus content or. adding organic matter. Studies are
available on the relationship of the' metal contents of soils to plant
growth (Chaney, 1973).
(f- !• — 6-1/2" -i •
Conductivity !
1 1
! i
Conductivity is an important soil characteristic that is frequently
neglected in routine analysis. Since salt content can dramatically affect
plant root growth and water balance, avoid planting in soils with a
conductivity greater than 2 miaohs /cm. Soils with greater conductivity
can be used only after rain water has leached enough salt from the soil
to bring it within acceptable limits, (i.e., less than 2 mmohs ) • This
process may take several weeks or months, depending on the amount of
rainfall and drainage characteristics. Salts may never leach from soils
in the drier parts of the country. Conductivity tests can be performed
along with the more routine analyses.
i I
STEP A-5. DETERMINING SOIL BULK DENSITY
i i
Cover soil is frequently compacted by landfill equipment during
spreading operations to bulk densities exceeding 2. fj g/cm3. Bulk density
can be determined by weighing two or; three undisturbed soil cores of a
known volume(e.g., 300 cm3) for each acre. If the density is greater
than 1.7 to Ii8 g/cm3, plant root growth will probably be severely
restricted (Bohrn, 1979). Compacted soil should at least be scarified,
and organic matter added to enhance the physical properties.
STEP A-6. AMENDING COVER SOIL
t
The soil'over the entire planting area should be amended with lime,
fertilizer, and/or organic matter according to recommendations from the
soils lab one to several weeks before anything is planted. These materials
should be incorporated into the top 15 cm of soil.
EJ STEP A-7. SELECTING LANDFILL-TOLERANT SPECIES
1 3/8" I
JOTTO
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*I — From the results of the experimental plots established in Step A-3,
i grasses and other ground covers can be selected for planting in the soil
• cover spread on the entire landfill..
SECTIONS S,
BEGIN
STEP A-8. PLANTING GRASS AND GROUND COVERS
_define.,j;he_best_planting«
technique for establishing grasses on landfills, but it is generally desirable
to embed the seed in the soil. Mulches have been used as an alternative to j
embedding the seed, but this approach is less likely to be effective on ad- j
verse growing sites such as landfills.' On steeper slopes, where embedding or
drilling is impossible, a mulch must be used to prevent the surface soil
layers from drying out and to hold the seed on the soil until it germinates
and establishes a reasonable cover.
i
Planting Steep Slopes
Several methods exist for dispensing seed onto the cover soil. Steep
slopes that are inaccessible to conventional equipjnent ^st_be_hydrgj-^
pprocesse'd"in" 6ne"operation~with"fertilizer, lime, seed, mulch, and enough j
tack to hold the mulch on the slope. iHydroseeded soil must not be compacted I
during spreading and must be very friable at seeding time. Seed will germ-
inate beneath the mulch on hard, compacted soil, but the roots will not
penetrate the soil surface and will succumb to drought. Although hydro-
seeding has been advertised as a miraculous process for vegetating slopes
and other areas with adverse growing conditions, results will be disappoint-
ing unless the soil is properly prepared with the right equipment at the
proper time.
Planting Flat or Gently Sloping Ground
i j i
I Many methods exist for spreading fertilizer, lime, seed, and mulch
i on flat and gently sloping ground (hand-spreading, use of cyclone spreader,
\ drilling, furrowing, etc.). The method chosen will be dictated by the soil j
; type and condition, and by other factors particular to the planting areas
to be determined by the contractor. To assure that the methods used are
suited to the existing conditions, these factors should be carefully
studied just prior to planting.
Barren Areas
Areas may exist on the landfill cover where plants will not grow
because of high' landfill gas concentrations. Replanting these areas will
generally not eliminate this barren area problem. Wood chips or large
stones can be used to prevent erosion and provide an aesthetically pleasing
appearance. If! gas is extracted or otherwise recovered from the landfill,
the ability of the cover soil to support vegetation will be increased.
Further discussion of this matter is presented in Step B-2. :-
j
If no gas is present in the areas of poor growth, the soil should be
i-,ic checked for the constituents listed in Step A-3 and for erosion washout.
r^^p:! replanting is necessary, the area may first have to be refilled, regraded
'" '—and- micro terraced.- _____ . —.—,-
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Cr TEXT
• STEP A-9. DEVELOPING TREE AND-SHRUB GROWTH "
i i
Efforts to develop a good cover of woody plants should begin by
ascertaining that 90 cm of soil is in place in areas where trees and
shrubs will be planted. Woody plants generally have a deeper root system
.and require better anchorage than ground cover species. Soil added to
_bring the_j?riginal cover to a depth of 90 cm should_.be,_selec.ted_.and_3pread.
according to Steps B-4 and B-5. If sufficient funds are available, a
barrier (Step B-3) should be placed beneath each tree-planting area to
protect the root system from harmful landfill gases.
! i
The least expensive and most practical means for establishing trees
on a completed landfill that has been closed for some time is to plant
seeds or small whips of species already establishing themselves on the
landfill. Some of these species may be available from the State nursery.
Since recently closed portions of landfills and older landfills with very
poor cover material are not likely to support many volunteer trees or
shrubs, consult Step B-8, a good reference (e.g., Harlow and Harrar, 1969)i
and/or the county a gricultura^a\gent_to_determine_ which £f the_volunteer
s~pec~ies~ is" b~est~suited fbV~the~ area;
I i
After the grass has been planted, a 1-or 2-year waiting period is
recommended before areas are selected for planting trees and shrubs.
If the grass cover with its shallow roots dies or fails to germinate
because of "the" influx of gases from the landfill, it is nearly certain
that other deeper-rooted vegetation (trees and shrubs) will not thrive
at these locations.
The procedures presented so far represent the bare minimum required
for establishing plants on a completed landfill. As the funds for land-
fill end uses increase the more sophisticated procedures described in the
next section can be used for establishing grass, shrubs, and trees.
t i
Because gas migration into the!root zone will adversely affect the
survival rate of grass, shrubs, and trees, active extraction of gas from
the refuse layers is recommended* This procedure, while effective, is
expensive. However, if the gas can be sold for its heating value, the
cost of the gas-extraction system may be recovered. If this procedure
is not practical, consider placing gas barriers between the refuse and
tree roots to prevent gas migration. These procedures are covered in
Steps B-2 and B-3. I
sorrc
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SECTION 3
i
VEGETATING LANDFILLS WITH ADEQUATE FUNDS
STEP B-l. CONSTRUCTING THE LANDFILL
Developing an end-use plan before construction or closure of the
landfill will increase the likelihood that a successful vegetation
program can be implemented. Factors to be considered in vegetating a
former landfill include refuse age, ; type, dep th, and compaction; _lpcation ,
of" degradable" or" rion-degradable refuse, proportion of refuse to daily
soil cover, amount and type of final soil cover, surcharging of refuse
with cover material, area climate, final contouring (including maximum
slope), and gas extraction. j
'.
9-* /3"
Minimizing "Gas Production
The amount of landfill gas produced during refuse decomposition is
generally related to the amount of putrescible or volatile material de-
posited in the landfill, age and depth of landfill, water infiltration,
etc. (Emcon Assoc., 1980). To minimize gas production, the ratio of
nondegradable to degradable material can be increased by including
greater quantities of nonputrescibles in the refuse or by increasing the
ratio of daily cover to landfilled refuse.
i !
Placing nonputrescibles (glass, plastics, metals, rubber, concrete,
etc.) in specific areas to -create nonbiodegradable refuse islands may
allow plants to grow in areas relatively free of landfill gases and
facilitate more efficient resource recovery in the future, tGases may
migrate into these zones from areas containing decomposable material,
but grass, shrubs, and trees should grow better above these islands.
Minimizing Surface Settlement
i
Surface settlement may have to be minimized in some areas so that
irrigation lines can be installed and maintained to support trees and
shrubs. Islands of nonputrescible refuse have minimum surface settlement j
and can generally support irrigation lines without the constant mainten- j
ance required in the areas containing putrescible refuse, where frequent !
breaks are caused by uneven settlement. Later surface settlement can also
be minimized by surcharging the refuse witfi the soil that will be used ;
s cover material in the future or by filling the area with shredded or —;
^Z.—baled-refuse. i *, . •
, ,
?i j \j t
-PA-237 (Cin.
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/•••••••••• 13 ••:''-'---'\
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3ECN
SECT:ONS
zcrz,
i Final Contouring
i A. critical consideration in landfill design is the slope of the final
i contours. A. steep-sided landfill slope allows for the placement of a
; greater volume of refuse, but it also promotes soil erosion and hinders
~J~vegetative establishment. Evidence indicates that slopes steeper than
r 3:l~(hbTizblitaTfvertic~aT.)^nh^
; component during the closing of a landfill. Since recommendations
! for maximum allowable slope are still a subject for discussion, one
} must practice good judgment when grading for final contours.
STEP B-2. EXTRACTING GAS
i
The most successful landfill-to-park conversions in the coming
years will incorporate a gas extraction system in the landfill to
reduce the volume of gases escaping into the final soil cover and inhib-
iting root growth. These systems will be compatible with gas recovery
operations and may .eventually p3y_for^a_poTt±on_o£_the^ park construction
ati3~maihtehance~requirements. ~
i
Induced Exhaust Systems
i
Extracting gas from within the refuse fill by an induced exhaust
system, as "is currently being done in several states, should aid plant
growth by reducing the quantity and pressure of landfill-generated gas.
The economic value of the extraction operations may end before gas
generation ceases, but successful plant growth may require continuing
operation of the extraction equipment. The soil in which the vegetation
established itself probably had a very low gas content: any sudden in-
crease in gas 'would be likely to cause severe plant stress.
i I
Patterns of Gas Contamination I
' j I
The gases of anaerobic refuse decomposition (primarily methane and
carbon dioxide) can migrate- from the refuse layers into the cover soil,
and in some cases into property adjacent to the landfill. The latter is
most likely to occur at landfills located in former stnd and gravel pitss
where the surrounding soil is very porous, facilitating lateral gas flow.
! ]
Gas contamination of the cover•soil will not be uniform ovar the
entire landfill site. Some areas will contain relatively high carbon
dioxide (>25%) and methane <>40%) concentrations, and consequently low
oxygen «6%) .contents. Other cover soil areas may be influenced very little
by the underlying refuse material.
Effect of Climate on Gas Production'
'j ~ ' i -.
Site visits to some 60 completed landfills within nine major
climatic regions of the United States generally revealed a high negative
:orrelation between plant growth and concentrations of methane and/or
*± carbon dioxide -in the -root .atmosphere _.(Flower-at._al. ^JL978) <>—Little——
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-variation in the magnitude of landfill gas production and consequent * ,
.""vegetation damage was observed among the different climatic regions, except
! for the arid southwest (Arizona), where concentrations of methane and
, carbon dioxide were found to be somewhat less than in the either other
i climatic regions.
' 1
"Gases from Hazardous Wastes
Very little appears in the published literature about decomposition
•i and gas generation in hazardous waste landfills. Shen (1981) states that
| most organic wastes will degrade biologically and chemically into gaseous
i components, but no data are presented to support this statement.
I
| STEP B-3. SELECTING'GAS BARRIERS
i
Since landfill gases may migrate into the final cover soil even with
a commercial gas extraction system in operation, special precautions should
be considered when planting trees and shrubs. The best planting procedure ,
would be to cover the entire__landfill_with_ain_impervious _soil layer .^.J
e(Iutt6n,~1980)"~of~synthetic lnembVane~to Keep gases from entering the final ;
cover soil. Provision must be made to release the gases from beneath j
the impervious layer. This barrier will also prevent water infiltration 1
j into the underlying refuse and thereby reduce leachate generation. If
!such a procedure is economically unfeasible, then gas barriers should at
! least be,.installed in areas where trees and shrubs will be planted. Of
I course, the grass or ground cover in other areas of the fill that do not
I have gas barriers will be subjected to gas contamination that may cause
i patchy areas of poor growth.
| j
! A variety of barriers are currently available to control gas migration!.
|A 30-to-60-cm-thick layer of impermeable clay spread over the final j
irefuse layer and followed by an adequate amount (>60 cm) of fertile soil I
Affectively prevents the upward migration of landfill gases into the root j
!zone. Polyvinyl chloride (PVC), hypalon, and other types of membrane j
.sheeting C>20-mil) also prevent gas migration (Matrecon, 1980). Special j
^installation requirements are illustrated in Figure 3. j
VEGETATION
1 "^"^^ COVER SOIL ^^X^^x,
i
SAND
SAND N
YNTHETIC MEMBRANE
Figure 3.
SEGiN
OF TEXT
Gas protection scheme using synthetic membrane
covering large areas-over former refuse fill.
i BOTTC
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.—The sand layers above and below the membranes provide physical protection —j
I during installation. Bentonite has also been effectively used to prevent I
CHOPPED j gas migration into tree and grass root zones. The trees and grass pictured
-E.--.D, i in Figure 4 were growing in 75 cm of soil spread over a 3-cm-thick bentonite
~V:,~:M i ]_ayer that was applied by hand over a rolled 15 cm clay base. Note the j
Si—poor grass growth around the mound where there was no gas barrier. At i
;r!l_least^0._cnu.o.f._soil .shouldJae ..spread .over..these -barriers_to insure~. _]
; adequate tree growth. < I
; i ! i
i The trench barrier system (a modification of the mound system) may be
; useful if soil mounds are not desirable in a particular area. Although
j this system (Figure 5) has been successful on a small scale (3 x 4 m) ,
j (Leone, et al., 1979) it would be preferable to secure a barrier all the
way to the soil surface and avoid leaving a portion of the cover soil exr
posed to the waste material and the entry of laterally migrating gases.
i 1
Another method that may be suitable for planting trees and shrubs
in small areas such as planting islands in parking lots involved the
^construction of a saucer lined with one of the impermeable polymeric
a*3^£. . . — —— .. — . .. -. - .t — . - *.,*— -^_ __
| materials previously mentioned and drained by an open U-tube installed at
the bottom of the saucer (Figure 6).{ The U-tube would allow accumulated
water to drain from the bottom and prevent gases from back-flushing into
the saucer. < j
3-1/8" !
Proper functioning of all the gas-barrier techniques mentioned
depends on the assumption that the gas barrier remains intact. Since
refuse decomposition is likely to continue for scores of years, refuse
settlement is also likely to continue for a similar time. Cracks or
breaks in the barrier resulting from such settlement may also permit gas
to migrate into previously uncontaminated areas, and areas that contain
gas may become free from gas. j
STEP B-4. SELECTING COVER SOIL
j
Many landfill operators cannot afford the luxury of selecting
from a variety of final cover soils because of their high cost or lack
of availability. Consequently, many revegetation attempts have failed.
Methods of selecting and spreading the first lajers of soil over the final
refuse layers have been examined (Lutton, 1980), but the final layers
of cover soil should be selected according to the criteria outlined below.
The first task in selecting cover soil is to determine what kinds
of soil are available. One, two, or more types of soil may be immediately
transportable to the site. The soil with a texture closest to a loam
should be selected for areas where trees and shrubs will be planted,
because they generally require a looser, deeper soil for root development
than do the grasses and ground covers. This soil should then be tested
I for the constituents listed in Step A-3. Five composite samples-con-
| sisting of five subsamples each (Step A-4) should be collected and sent
I to a certified soil testing laboratory if the soil appears to be uniform.
t~~More samples will be necessary if a variety of soils are to be used for
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Good tree and grass growth in 75-cm soil mound
over a 3-cm thick layer of bentonite.
Tre
60
cm Cover
Soil
Refuse
90 cm Loamy Sand
30 cm;Sand or
Round Gravel
20-mil synthetic membran
10 cm Diameter ;
PVC "-Vent Pipes sQTTC
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LAoT Li
.Figure 5. Gas prevention scheme for small planters. Vent
i pipes should be spaced no more than 2 m apart.
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20-mil Polymeric
Liner i
Soil Base
5EG1N
LAbT •_
r 75/
Curb
Parking Surface
Demolition Base
Refuse
10 cm. Diameter PVC
Vent Pipes
^d Water Level in Trap
Refuse
Figure 6. Gas protection scheme for vegetation planting
island in a paved parking lot located over a
former refuse landfill. .
_i_: i_
': 18
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DRG--ED !
HEAD. !
cover. This decision should be made by a qualified soil scientist, because
it is likely to be different for each site. The soil should be tested
before it is sent to the site, because of the relative ease of amending
the soil before or during spreading.
^ STEP B-5. SPREADING COVER SOIL.
The clay soil layers should be spread over the final refuse layers
to prevent infiltration into the landfill according to recommendations
in "Evaluating Cover Systems for Solid and Hazardous Waste" (Lutton,
1980). Since this soil will not adequately support vegetation, additional
soil should be spread in the manner described below.
||
One of the most critical steps in reclamation projects is the actual
placement of cover soil. Earthscrapers are usually used for this task,
and the end product is a series of horizontal layers of more or less loose
soil, with vertically and horizontally adjacent compacted zones. Bulk
densities on the order of 2.0 g/cm3 in the wheelings of earthscrapers are
iamon .w.ith .1..2_g/cm^2in.the. loosely ..spread, soil-between -the-wheels.™ The,~
compacted zones have been shown to restrict root growth and downward
movement of soil moisture and may contribute to surface-water ponding. j
Soils that compact most easily include those of clay texture, those low j
in organic matter (e.g., subsoils), and any soils that are wet during j
spreading. 9-1/3" j j
1 i i
The avoidance or elimination of these compacted layers can be a key j
to a successful reclamation project. They can be avoided by mixing organic
matter with the soil before it is spread, spreading soil only when it is j
dry, and by using earth-moving machinery other than the normal earthscraper.
Dragline excavators, bucket-wheel excavators, forward-acting shovels, and
bulldozers have been proposed, but may result in considerably higher
operating costs than earthscrapers (McRae, 1979). ]
1 I i
If several different soils will be used in the final 60 to 90 cm of j
cover material spread over the gas/water barrier, they should be mixed
together and spread as a unit, not in separate layers. Spreading soil
in a thick layer will promote les-s^orer-all compaction, increased water
movement, and better root growth than spreading in several thin layers.
I ' M
If soil must be spread in a conventional manner and bulk densities
are above 1.7.to 1.8 g/cm , consider several procedures currently available'
that will promote better root growth and soil water flow and ultimately j
provide a more successful reclamation project. j
I !,
The destruction of the compacted layers by means of subsoiling or
deep-tine ripping after the full thickness of soil cover has been placed
will encourage better root growth, but it is not usually completely
i effective. The available machinery most often cannot draw the tines deeply
j enough or sufficiently close together; or the operation is quite often
• performed at the wrong soil moisture (i.e., too high) (McRae, 1979). ,
•5 Q
o, v
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'"-—Some success has been achieved with ripping each layer after it is spread —.
: and with the use of specially designed subsoiler such as a vibrating ;
subsoiler or the double-digger. This modified equipment may be used to \
incorporate the organic matter into the deeper soil layers. Organic matter
should preferably be mixed with the cover before it is spread. !
i " i !
i . ' .
J)rganic_ amendments areJbeneficial to the physic^l^_.chemicaJL,._and_
biological properties of most cover soil. Addition of organic materials
decreases bulk density and increases water infiltration and retention.
Some organic materials provide an energy source and improve the environ-
ment for beneficial soil microorganisms. These materials include humus,
peat moss, manure, crop residues, food wastes, logging wastes, industrial
organics, leaf compost, composted sewage sludge, or refuse compost. A
soil bulk density of 1.2 to 1.4 g/cc is desirable depending on soil texture.
A higher density can generally be tolerated in a coarser soil. Gypsum,
perlite, or vermiculite may also be 'disced or chiseled into the existing
soil. These materials should also be incorporated into as deep a soil
layer as possible, preferably at the time the cover soil is originally
^US-
pread on the, landf ill,.or_o_n_ thejgas/liquid barrier._
."': rrvr .<-•
Soil structure can also be improved by establishing a grass or ground
cover for several years before planting trees and shrubs. The processes
of freezing and thawing, rainfall, earthworm and insect activity, perco-
lation, and leaching will also help increase soil porosity and promote
more desirable physical properties. 'This process of reestablishing the
network" of soil pores and fissures that provide adequate air exchange with
the atmosphere may take many years.
STEP B-6. SOIL DEPTH
1
It has been reported (Bohm, 1979) that 60% to 80% of tree root volume
in the forest can be found in the top 20 cm of mineral soil and that most |
of the fine feeder roots are in the top several centimeters. Roots are i
likely to be somewhat deeper in open plantings such as parks and golf !
courses than in the forest situation. The remaining portion of the root j
system is located at varying depths (from 20 to 90 cm), depending on |
species and soil characteristics. Thus a 30-cm soil may normally accommod-
ate a good portion of root volume; but on a landfill, this shallow soil j
would dry out.very quickly during seasonal drought spells and would not |
adequately support large trees.
Because of the excessive cost of covering the entire landfill with
deep, rich soil, the planner should consider spreading 90 cm only in
those areas where trees are to be planted. This layer need not be made
up entirely of topsoil, but the depth at which most of the feeder roots
will be growing (20 cm) should be topsoil., At least 60 cm of soil should
be spread in areas where trees will not be planted. The depth of cover
soil should allow enough space for grasses and other stabilizing vegetation
to develop an adequate root system, provided landfill gases are not present
in the cover soil. I
2GTTO
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I-
—STEP B-7. LOCATING AREAS UNSUITED FOR TREE AND SHRUB GROWTH
i ' i ;
; Areas unsuited for tree and shrub growth can be located either
\ before or after selecting specific sites for tree and shrub planting.
; Possible indicators of a potentially poor growth site include dead or
vegetation, anaerobic soil, high soil temperatures, thin cover soil.
Areas with Dead or No Vegetation i
• i i
The simplest method for locating unsuitable areas for trees and
shrubs is to observe existing vegetation patterns. Areas where soil
appears thin will most likely have very little or no plant growth
(Figure 7). The C02 and CH^ concentrations in these soil atmospheres
are likely to be high and limiting to plant establishment. Soil temper-
atures are frequently elevated in these so called "hot spots", ranging
anywhere from! a degree or two to more than 20°C above surrounding un-
contaminated soil. Such barren areas should be avoided when selecting
sites. for_j:rees_and, shrubs. j ,
I I
Anaerobic Soils j
1 ' i
Anaerobic soil conditions may not occur until after plants have been :
growing for some time. Vegetation will die if the soil becomes contaminated
with the gases of anaerobic decomposition. If plants of different species
in an area are dead, dying, or nonexistent, chances are that the soil has ]
been contaminated with gas and that this area is poorly suited for growing
plants of any kind. If plants of only one species appear to be affected,
one should have a qualified plant pathologist or county agricultural
agent evaluate the problem, as there may be a disease or insect problem.
Some of the following -.tests may be performed to check for anaerobic soil
conditions. , i
!
Direct Gas Measurement— '• \
Direct measurements of ^combustible gases can be made in the root zone i
of an area where one wishes to plant. A gas sample is drawn from the soil j
through a holev made with a barhole-maker,to an explosimeter (the type of 1
instrument frequently used by the utility companies when looking for leaks j
in their underground gas lines). Readings taken from the 30-, 60- and 90- j
cm depths generally present an accurate picture of the amount of gas in the,
cover soil. Planting is not recommended if any combustible gases are j
present in the cover soil. If gas is not extracted from the landfill and j
no clay or other barrier exists over the refuse, then portions of the soil j
cover will most likely become contaminated.
I 1
The carbon dioxide and oxygen contents of the root zone should also
| be measured. Soil gas samples can be taken from bar holes with Bacharach
i Fyrite or other carbon dioxide and oxygen indicators. High carbon dioxide
: concentrations are sometimes found in landfill soils despite the absence
2CTTC
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:;.;.: 21
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-------
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^ v
in
in "H
>• i
V."1
CO
CX3
Nl'
IsJ-
n i tn (I1 m
1V! :.' '•'' O
in
O
Figure 7. Area with shallow cover soil and consequently little or no plant growth
.^.-L—
r"" ?' I'J "j f- ^ O
j> Q uj ^ IH > -H
J 1
-------
HEA
C
55
-of combustible gases. The high carbon dioxide content is toxic to plants —
and indicates the possibility that soils may be anaerobic at times. In
fact, current scientific evidence indicates that carbon dioxide is probably
more toxic to vegetation than methare. (Arthur et al., 1981). Root
growth of some plant species is inhibited when soil oxygen content decreases
_to 10%. Other species are not adversely affected by 02 concentrations as_
low as 1% (Flpw^r_ej:^l^,_]JJ8^.__^he_Jtog
_
"low oxygen concentrations are often highly correlated with each other.
Though an area may have been chosen for planting as a result of low
combustible gas readings, differential settlement and varying gas production
rates may saturate an area that was once free of landfill gases; the reverse
may also occur.
i
Physical Characteristics —
The soil. itself should be examined to detect anaerobic conditions.
In many cases, unpleasant odors of anaerobic decomposition are quite
noticeable in ] soils that are lacking in oxygen. Such soil is generally
j darker, damper, and more_clay-like_ (less_ friable)_ thj^J -™ __ .3
r*^Erob"ic~condition. J"lAerobTc~s6ils~that do not contain measurable landfill
gases do not tend to accumulate as much moisture as anaerobic soils.
! I
Tests for Ammonium-nitrogen, Manganese and Iron —
Soil tests will also generally reveal higher amounts of ammonium-
nitrogen (NH^-N) and available manganese (Mn) in anaerobic than in
aerobic" soils. The available iron (Fe) and zinc (Zn) content may also be
considerably higher in soils that have been anaerobic for an extended
period of time.
H igh_Soil Temperatures
- : ~ i
Temperatures in anaerobic soils 'are frequently higher than in nearby
aerobic soil—from a degree or two to perhaps 20° or 30°C in extreme cases.;
The reason for these high soil temperatures is undetermined, but it may
result from microbial activity, chemical reactions, and/or underground
fires. !
Thin Soil Cover
The amount and quality of soil covering the refuse in a landfill
has frequently been found to be inadequate for vegetation growth.
Measures for correcting these deficiencies are outlined in Steps A-2,
A-4, A-6, B-4:and B-6.
Settled Areas
i
Refuse and soil settlement caused by loss of solid refuse material
through biological and chemical decomposition will create an undulating
surface that causes water to accumulate in low areas during periods of
rain and irrigation. Trees, shrubs,:and grass in flooded areas may
eventually die if water remains for extended periods and/or if rainfall
-is frequent. !Furthermore, undulating greens will not be tolerated in
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-most golf courses. Operation of farm equipment may also be hindered by
uneven surfaces. Provisions should therefore be made to accommodate
settlement. In extremely dry climates, on the other hand, plant growth
may be enhanced in the settled areas because of increased soil moisture.
; . i
.STEP B-8. SELECTING TREE AND SHRUB MATERIAL
SEuhM
The end use for the completed landfill must be known before plant
species are selected. The desired species for a nature area may be
different from those selected for a park or golf course. Once an end use
has been selected and the general type of vegetation has been determined,
the following guidelines will be useful.
I I
The first consideration should be the great variation in species that
grow in widely separated geographic areas on this continent. Choices
should be limited to plants that are known to be adaptable to the areas
and that will be commercially available there.
, __ ^ sjecond_consideration shojuld be_that jrefuse_quaJLity, _quantity, age,
\ " and depth differ markedly from landfill to landfril~and™from"one" geographic"
] area to another. For instance, a former open-burning dump may generate \
i little landfill gas and undergo only minor settlement because it contains i
\ only small amounts of biodegradable organics. Variations in climate are |
\ also represented across North America. These factors and others interact }
to produce widely different environmental stresses as well as varying gas !
production rates and mixtures. I
i i
The third item to consider is that field data indicate that when the
combustible gas and/or carbon dioxide concentrations are excessive and
the soil is anaerobic, few if any tree species are able to survive.
i i
Despite these limitations, research results have indicated that trees
and shrubs grown successfully on completed landfill sites have a variety
of common characteristics (Flower et al. , 1981, Oilman et al., 1981).
.i _ !
Factors to be considered in choosing the tree species to be planted
include growth rate, tree size, rooting depth, flood tolerance, mycorrhi-
zal fungi and pathological considerations. A discussion of these factors
follows . i
Slow-Growing vs. Rapid-Growing Species
I i
Evidence ! indicates that slow-growing trees are more tolerant to land-
fill conditions than rapid-growing species. The faster-growing trees i
generally draw more moisture from the soil and would therefore require i
more irrigation to maintain growth comparable with their growth on a non-
landfill area. But, if comparison with non-landfill areas is not a
concern, a faster- growing tree may be more desirable with its more quickly
produced vegetative cover. Species classified as fast growers produce
more total growth on a landfill than the slow growers if they are regularly
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-irrigated during the first 3 years after planting. Table 4 lists some of"
the slow moderate- and rapid- growing tree species found in the United
cao;:?SO | States. | • |
HEAD,
BEGIN
i 1
TABLE 4. SOME SLOW, MODERATE AND
SECTIONS ! FOUND IN THE
A|^ -r - - -----
RAPID GROWING TREE SPECIES
UNITED STATES
-
,
.
Slow
Moderate
Rapid
Serviceberry '
Sargent cherry
European hornbeam
Yellow-wood '
Ginkgo j
Flowering dogwood
! 6-1/2"
Littleleaf European linden
European white birch
October Glory red maple
Kentucky coffee-tree
Hackberry j
Kwanzan Japanese flowering
cherry
T
Summershade Norway
maple
Shademaster thornless
honey locust
Sawtooth oak
Hybrid poplar
Willow oak
-Tree-of-heaven- —as
Silver linden
-.EC:'
LAST
-*— t t i"*
More complete lists are available in Pirone (1978) and Fowells (1965), or
at the county agricultural agent's office.
1 j
Small versus Large Plant Material I
i I
Results of limited investigations indicate that trees planted when
small ( 1 m-tall) show significantly better growth on landfills than do
those of the same species planted when taller than 2 m, regardless of
species. This phenomenon is related to the ability of a small tree to
adapt its root system to the adverse environment in the cover soil by
producing roots close to the surface (i.e., away fvom the high landfill
gas concentrations that occur deeper in the soil). Roots of larger trees,
on the other hand, start much deeper and sometimes cannot produce much
growth toward^the surface before being killed by landfill gases. In fact,
by the time the larger tree adjusts to the landfill by attempting to
produce a shallow root system, the smaller specimens, which started with
a shallow root system, may actually equal or surpass the larger trees.
If it is necessary to plant trees taller than 1.5 m, plant them on a
raised bed to'provide an adequate depth of soil uncontaminated by land-
fill gas to accomodate roots already developed in non-landfill soil.
Larger plant material can be used only if landfill gas is kept from the
root system and the plants are well irrigated.
! , •
Volunteer Species <
j ! i
' J Although volunteer tree species (early" successional species) have not
.~lTEj been specifically studied on landfills, they are generally, very adaptable—
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-to poor soil conditions and are often the best species for establishing ;
trees in a low public-use area of a landfill. Volunteer species indigenous
to several areas of the country are given in Table 5. <
TABLE 5.
VOLUNTEER (PIONEER) TREE SPECIES INDIGENOUS TO VARIOUS
GEOGRAPHIC AREAS OF THE UNITED STATES
Southeast '
1
Mimosa i
Eastern cottonwood
Sweetgum j
Red stemmed dogwood
Loblolly pine'
Eastern red cedar
Sumac i
Boxelder '
, _ j. _ 6-1/2'
Northeast j
Gray birch '
Mulberry !
Paulownia 9-1/3"
Catalpa- i
Eastern red cedar
Red stemmed dogwood
Red maple '
Bayberry j
Quaking aspen
Hybrid poplar
Sumac j
Boxelder ]
Black locust !
Northeast-Great Lakes
Jack pine
Quaking aspen
Pin cherry
Red stemmed dogwood
Paper birch
Boxelder
Plains States
Choke cherry
Boxelder
Red stemmed dogwood
Black locust
Northwest
Red alder
Red stemmed dogwood
Quaking aspen
Boxelder
Appalachia
Black locust
Boxelder
Red stemmed dogwood
Puerto Rico
Mimosa
Acacia
West-Indian locust
Hollywood
Dominican mahogany
Lignum vitae
0cr;;N
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Additional information on volunteer species" can be found in Harlow and
Harrar, 1969., , .
-.:=.•••;.' 26
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•—Natural Rooting Depth
Tree and shrub species that enjoy shallow root systems were found to
be significantly more adapted to landfill sites than species requiring
a much deeper root system (Table 6).;
_TABL.E_6J___VERTI.CAL_DISTRIBUTIQN jpFJIREE^RQOTS_.IN .LANDFILL .AND.
' NON-LANDFILL SOIL
Species
Average Depth (cm)
On Landfill
Off Landfill
i Japanese black pine
1 Norway spruce
! Hybrid poplar cuttings
UsaHoney- locust—I — 6-1/2"
Green ash ]
Hybrid poplar!saplings
7!
5''
6
8'-
9
9
9
4
13
1-7
15
13
c
9-1/3" I
aSpecies at top of list were more adapted to the landfill than those
at the bottom (Gilman, et al, 1981).
The deeper roots are subjected to higher concentrations of landfill gases
and lower concentrations of 02- Some species can avoid this adverse gas
environment by producing a shallow root system. Observations at the South ;
Coast Botanical Garden in Palos Verdes, California (a former 87-acre land- j
fill site) showed that shallow-rooted plants are seldom affected by landfill
gases; in some cases, however, root damage has occurred in the larger trees
and shrubs (Flower et al., 1978). Several texts are readily available I
showing the natural rooting depth of woody species (Fowells, 1965; Harlow j
and Harrar, 1969), however these lists are incomplete.
i
The fact | that trees growing on landfills generally develop .shallower
roots than the same species growing off the landfill emphasizes the need
for frequent irrigation of landfill soils planted with woody vegetation—
especially if gas is not extracted from the refuse. If landfill gas is
kept out of the cover soil, roots should be able to grow deeper. Species
excavated for extensive root studies on landfills had a significantly
larger portion of their root system in the top soil layers (Figure 8)
than in the deeper layers. But, roots were much more evenly distributed
depthwise on trees growing in the nearby non-landfill control area .
(Figure 9). j i :.
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27
t 4" / j ;
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-, p
O
co
CO
00
Eigure 8. Excavated green ash on landfill showing most roots in top soil layejr
1 J'!
: t > p.i o O ;; ™
,JJ ", C.' r- r" > u
,t^ P! U) :' -J > -t
° -
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4 PC- -
c
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C
Figure 9. Excavated green ash in control area showing even
| distribution depthwise of root system.
BOTTC
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, Because many roots are found growing close to the surface and since the i
! top several centimeters of soil regularly dry out for extended periods ]
DROPPED ; in the temperate zone of North America, landfill soils must be irrigated i
more frequently than nearby non-landfill areas to ensure good vegetation
growth. Also, our field studies indicate that landfill cover-soils do
_not maintain as high a moisture content as the same soils off the land- 1
_fill. This ._may.J>e_due.__tQ_a._lac.k. of ,,ve,r .t ical_upwaK.d_transport_Qf_jpaQi.st.ur^ j
through the refuse and greater evapotranspiration on the landfill. 1
i j
Lysimeter studies have shown that plant roots can penetrate into
refuse zones,' but these studies fail to report on the gaseous conditions
in the refuse. More than likely, the refuse was not in an anaerobic
state, since most plant roots soon succumb in such environments. Few
roots on the one landfill studied ever grew deeper than 20 cm. Those
that were deeper always died before reaching the refuse—probably from
the lack of oxygen in areas close to the refuse.
! I
It is difficult to know whether tree roots will penetrate a synthetic
^membrane j>laced_pver .^he_refus_e as a_gas andJLiquid_barrie_r. If jthe__seal '
'remains intact (i.e.,"if settlement does not disturb the integrity of the j
membrane), and if landfill gas is kept from the soil above the seal, then j
roots may penetrate 1 m of soil and grow to the membrane. Root growth j
may continue if water has drained away from this point. The propensity
for roots to attempt to penetrate this layer would be species-dependent
(i.e.,"the shallower rooted species are not as likely to penetrate the
membrane as the more deeply rooted trees). Also a factor is the extreme
force required to penetrate a 20-mil PVC membrane. Research in this area
is lacking, so no definite answers exist presently. Techniques such as
surface fertilizing (as opposed to fertilizing at depth, the standard
procedure for- tree fertilization) and frequent light irrigation will
promote shallow-rootedness. Since the roots will be shallow, irrigation
will be required to maintain the trees and shrubs on such an area.
i i
The root systems of grasses are generally much shallower than tree
roots, so these roots should not penetrate gas/liquid barriers if at
least 60 cm of cover is present above the barrier.
Flood Tolerance
__~~ Our field data indicate that the changes produced by landfill gases
in the cover soils are similar to those imposed by the flooding of soils;
the difference is that the high moisture content is lacking on a landfill.
Thus species that are resistant to wet feet (flooding conditions) may do
well on landfills only if they are supplied with adequate water. Dry-site I
species should be planted if water will not be readily available
Size of Plants at Maturity
Another factor to consider when selecting species for landfills is
size of the tree at maturity. If the only cover soil available for root
growth is relatively shallow (30 to 60 cm), a tree should be chosen that
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'—- remains relatively small at maturity; otherwise there is a risk that the—
tree will topple during high-volocity winds. If a deeper soil cover
(>1 m) is available to the roots, the risk of windthrow will be dimin-
ished because the root systems has adequate soil space to produce anchor
roots (provided landfill gases are kept out of the cover soil and the
trees are irrigated). A number of publications contain information on
tree height aj^maturity (^owells,._!965_;_Pirone, 1978)). Th_e__c_ounty_
agricultural agent, local nurseries, and landscape architects can
provide information for a particular locale. Some of the smaller trees
and shrubs are listed in Table 7.
i
*
TABLE 7. SOME SMALL TREES AND SHRUBS (LESS THAN 9m TALL
i AT MATURITY)
Common.Name
Latin Name
;«*
Upright European^hornbeam
-Servic'eberry ~~ 5-1/2"
Hawthorn |
Goldentrain tree
Flowering dogwood
Kwanzan cherry
Black chokecherry
Common chokecherry
American elder
Sawtooth oak
Osage-orange
•Crabapple
Virginia pine
Eastern red cedar
Carpinus betulus f. fastigiata
'Amelanchier spp.
Crataegus spp.
Voelreuteria paniculata
Cornus florida
Prunus serrula'ta 'Kwanzan'
Aronia melanocarpa
Prunus virginiana
Sambucus canadensis
Quercus acutissima
Maclura pomifera
Malus spp
Pinus virginiana
Juniperus virginiana
OCUi
;n '•
Cr TEXT 3
Trees that are small at maturity should be chosen if cover soils are
shallow, if ;gas is not extracted from the fill, or if a gas barrier
is not installed. !
I
Mycorrhizal Fungi
Mycorrhizal fungi in association with plant roots have been shown
to greatly increase water and nutrient uptake by the plants. This
symbiotic association has been successfully used in reclamation of coal
strip mines. Mycorrhizae may also aid in successfully establishing
vegetation on completed dump sites, since landfill cover soil frequently
has a poor capacity for holding nutrients and water. Spore- and
mycelium-inoculated soil has been tested for its ability to promote
mycelium development on trees in landfill cover soil (Telson, Leone, |
and Flower, 1980 personal communication). Results of limited experiments
indicate that both forms of inoculation may be viable alternatives to j
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BEGIN
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planting trees in un-inoculated soil; however, the spore inoculum appears
to be more suited to areas of higher gas content. The roots may be j
inoculated directly just before planting to increase the likelihood }
of successfully establishing the beneficial mycorrhizal relationship.
; i
Pathological Considerations i _
The selection of trees, shrubs or grasses should always be based on
their ability to withstand attack by damaging diseases or insects common
to the given area. The county agricultural agent or soil conservation
service should be contacted, as they can frequently provide valuable
practical information concerning disease and insect-resistant plant
material, optimum planting time, proper fertilization, and other
amendments critical to an insect and disease control program.
i !
STEP B-9. PLANTING AND MAINTAINING VEGETATION
i J
Trees and shrubs survive best'if planted in early spring or fall.
The Extension Service, or Soil Conservation Service can ^identify_which_
~plantlng'~time~Ts "best for~a "ipecific area and species. Do not plant
during the summer. Plants purchased from a nursery and delivered to the
site should be planted as soon as possible. Bare-rooted material can
dry out in a matter of hours if left in the sun. Balled and burlapped
material can be left for some time longer, but it must be irrigated j
within a day or two, depending on the weather conditions. One person
should not be scheduled to plant too many trees in one day. Schedule
the work load so that only the trees that can be planted in a day
are present on the site. In the long run, it may be more desirable
to schedule a pick-up or delivery of plants each day, if practical. If
all the trees must be delivered on the same day, arrangements should
be made for storing the plants in a shaded, preferably cool, indoor
environment free from wind. Regardless of how the plants are stored or
how soon after delivery they are put into the ground, an irrigation truck
or other water-supplying vehicle should be made available to deliver j
several gallons of water to each tree at the time of planting.
-j ^ j
A planting hole about twice as wide as the root mass diameter and
up to 15 cm deeper than the deepest root is well suited for trees and
shrubs. Care should be taken to avoid compacting the sides of the
planting hole; such a step might promote prolific root growth inside
the original hole but inhibit root 'penetration into the surrounding
soil.
Mix some of the original cover soil with some loamy textured material
(preferably a highly organic soil) and spread enough of it in the bottom •:
of the hole to make a 15-cm deep layer (50:50 mixture would be a \
desirable combination). Hold the main stem of the tree or shrub and |
fill in around the root system until the hole is half filled. 'Gently I 30T70
press the soil down with the sole of your shoe; do not pack it down. i IMAGE
i GUTS! i
38"-
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§ 3/3"
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~T—During the backfilling process, be sure to relocate the roots so that their
I depth is equal to their original depth in the nursery. The latter can
; usually be determined by letting the roots hang freely before planting.
i Do not compact all the roots at the bottom of the hole. Spread them out
I as much as possible. At this point, the soil should be watered so that the
; entire root system has been moistened. This step may take one to several
•fs~ gallons, depending on tree size. When the water has all soaked into the
'~"~
C
fill the rest of the hole with the soil mix and gently press the
soil down with your foot. Form a ridge around the stem with an inside
diameter about equal to the extent of the root system and fill this well
with water. These simple procedures will retain all possible moisture
from rainfall and irrigation and help trees survive through the most
critical first season. Mulching with wood chips, bark, sawdust, grass
clippings, plant debris, or many other materials can help control water
loss by reducing weed growth and evaporation from the soil surface around
the trees. i i
The principles set forth above for planting small, bare-rooted trees
i generally hold for planting older, larger balled-and-burlapped^specimens.
h*1Tfe~do~h"ot~reconmend planting" trees older than~2 "to ~3~ years", "6V taller" than" ;
j 1 to 1.5 m with root systems 15 cm or more below the soil surface unless
! specific provisions for preventing gas migration into the root zone have
! been implemented and the soil is at least 90 cm deep. If it is impossible
! to obtain small seedlings for planting, several additional provisions are
i necessary for,the larger trees. First, more water will be required at the
I time of planting and during subsequent irrigation periods to saturate the
soil around the root system. Second, each of the trees must be supported
with at leas t^ two stakes and preferably three.
! i
The principles of maintaining plant material on completed landfill
sites are no different from those for non-landfill areas except that
additional irrigation is required. Soil with a low nutrient status must
be fertilized, and soils with the wrong pH (below 5.5 and above 7.0) must
be limed or acidified to desirable limits. The pH and nutrient levels in
the soils should be tested periodically (every 2 to 3 years) after plant-
ing. Fall is the best season for such testing so that any necessary
soil application can be made in early spring. The county agricultural
agent and Step A-4 can provide information on proper soil sampling methods
and interpretion of the test results.
i i
Irrigation is an extremely important requirement for establishing and
maintaining healthy plant material on former sanitary landfills, particul-
arly during the first 2 to 3 years after planting. After this time, roots
may have established a large enough system to withstand moderate drought
periods; however, irrigation should be practiced during extended hot,
humid weather, even for large, established trees. This additional watering
is needed because of the shallow roots close to the landfill soil surface |
where there is little available soil moisture during extended dry periods. ;
In-ground irrigation systems require continual repair, since settlement
is likely to cause frequent breaks in the pipes and thus increase main-
tenance costs. Various above-ground, expandable joint irrigation systems —
ire_available. ; . ^ —
33
iUi ;L
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.— Plants should be protected from disease and insect infestations an3 i
damaging animals. Several animals enjoy chewing the bark of certain j
: species during the winter. Check with the county agricultural agent and ;
> nurserymen to see if the selected species are susceptible to such attack. ;
• Some species are particularly vulnerable to winter desiccation. The j
' county agent can recommend procedures for overcoming this problem. !
^ Excellent instructions.-for-tree .maintenance-are-provided by Pirone -(1978) .
j. _ 6-1/2'
i
9-1/3"
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SECTION 3
i
LANDFILL CONVERSION: A HYPOTHETICAL CASE
This section uses a hypothetical example to illustrate the pro-
cedures described in this manual for closing a landfill and converting
it into a multiple-use recreational facility where adequate funds are
available to. select from a variety of cover materials, gas barriers,
and tree species.
For_this hypqthetical_landfill,_ a_landscape_ architectjrecommends
that a larger variety of end uses be incorporated into the reclamation
plan, including a nine-hole golf course, botanical garden, toboggan run
picnic area, | nature area, tree and shrub nursery for replacing dead
plants, bicycle paths, and campgrounds.
9-1/8" I
'Ideally, gases should either be extracted from within the landfill
layers or the entire, landfill covered by a gas barrier with passive
gas vents. The following suggests methods for developing the end use
where neither a complete gas extraction system or gas-barrier was
instituted. ( . !
Consider the type, age, and depth of refuse when choosing areas to
locate the various recreational facilities. Gas problems are likely to
be somewhat less severe in the older, shallower, and least putrescible
refuse areas, so they should be chosen as sites for the botanical garden
and nurseryJ Any area receiving only demolition debris would be well
suited for these uses. If"putrescible materials are present (as is
generally the case), install one of the gas barrier systems described
in Step B-3 and spread a high -quality soil above it. If little or no
putrescible material was placed here, then check for combustible gas
at the 60-and 90-cm depths (see Step B-7) in 10 to 15 locations per acre,
since gases can migrate from adjacent areas containing putrescibles and j
adversely affect vegetation. If combustible gas readings are consistently.
100% of the lower explosive limit or higher in concentration, a gas j
barrier should definitely be installed (Step B-3) before additional soil
is spread (Step B-5) or before trees and shrubs are planted (Step B-9).
Cover material can be removed and stockpiled to give a total depth of
90 cm in tree-growth areas. Trees should not be planted on a landfill
without a gas-barrier, since more than 50% of unshielded specimens may
be killed during the first year after planting. An above-ground irrigation
system should be installed so that every tree will be watered during the
•growing season. i
3 3/8"
j
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1
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The trees on the golf course can be planted in soil mounds under-"
laid with a suitable gas barrier such as 20-mil PVC sheeting, a 30-cm-
thick clay layer, or a 3-cm-thick layer of bentonite. This method does
not protect the grass in the fairways, however. No remedy exists for
this problem, and replanting will not help unless the gas later
moves away from the area. The course superintendent can check for this—<
_pccurrence._je.yery_Jl_.-or _2_.months._after,_the problem .arises.—If-the-problem ',
persists, consider converting the area into a sand trap. The course j
architect may even consider locating the sand traps 1 or 2 years after j
the fairways are established so that they can all be situated over areas
of gas effusion where they will serve as passive gas vents.
I i
A system must be designed to accommodate settling beneath the
greens, and perhaps the tees,, since these areas must remain flat.
Reinforced concrete slabs can be installed under each green so that, as
the ground settles, the green will move as a single unit and remain
flat. Unfortunately, it may not retain the same pitch.
i I
The_nature area can .be ..planted, withjaative..volunteer jtrees »_shrubs,.
and grasses in a fashion simulating natural succession. If barriers are
not installed, the trees and shrubs should be planted as seeds or 1-year
whips so that the root systems can adapt to the soil conditions. A 90-
cm cover of soil should be placed over the refuse, and the soil should be
checked for'nutrients (Step A-4) and bulk density (Step A-5). Areas
that do not,support plant growth can at least be used for educational
purposes. Such areas can dramatically demonstrate the effects of gas
kill on vegetation.
i
The picnic areas, tobaggon runs, and camp grounds should be seeded
with grass and perhaps other ground covers if desirable. Species should
be chosen that performed best in the experimental test grounds established
several years earlier (Step A-3). jBare spots where no vegetation grows
because of soil gas contamination can be covered with stones or wood-
chips to help control erosion and make the area presentable. Trees can
be planted .in groves if a gas barrier is placed 90 cm below the
soil surface.
A perennial maintenance program must be instituted to keep this
multiple-use facility operating effectively. Dead trees must be removed
and new ones must be planted. Living trees must be fertilized, pruned,
and treated(for insects and diseases. Grasses must be maintained and
the nursery, botanical garden, and golf course will need special attention
Erosion must be checked in bare areas that develop. The soil surface
must be maintained in areas of uneven settlement throughout the park,
and the plants must be irrigated more frequently than those on off-
landfill parks. A reputable tree expert company, arborist, or land-
scaper should be retained for professional services and recommendations
throughout the life of the park. \
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REFERENCES
Arthur, J.;J., I. A. Leone, and F. B. Flower. Flooding and Landfill
Gas Effects on Red and Sugar Maples. J. of Environ. Qual. 10:431-
433, 1981.:
1
Bohm, W. Methods of Studying Root Systems. Springer-Verlag,
Berlin-Heidelberg, 1979. 188 pp.i
I 1
Chaney, R.!L. Crop and Food Effects of Toxic Elements in Sludges and
-Effluents,-! -In: :-i.Prbceedings on Recycling -Municipal-Sludges-and- 2s*j
Effluents on Land. Nat. Assoc. State University and Land Grant Colleges,
U.S. Environmental Protection Agency, and U.S. Department of Agriculture
Workshop, iChampaign, Illinois, 1973. pp. 129-141. j
! !
EmcoJi Associates. Methane Generation and Recovery from Landfills.
Ann Arbor Science, Michigan, 1980.[ 139 pp.
i
Flower, F. B., I. A. Leone, E. F.:Gilman, and J. J. Arthur. A Study
of Vegetative Problems Associated with Refuse Landfills. EPA-600/2-
78-094. U.S. Environmental Protection Agency, Cincinnati, Ohio,1978.
142 pp. ' j
* , J
Flower, F. B., E. F. Gilman, and I. A. Leone. Landfill Gas: What It
Does to trees and How Its Injurious Effects May be Prevented. J. of
Arboriculture, 7(2): 43-52, 1981. ;
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Fowells, H. A. Silvics of Forest Trees of the United States. U.S.
Department .of Agriculture. Handbook No. 271, 1965. 762 pp.
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Gilman, E. |F., I. A. Leone, and F. B. Flower. Critical Factors
Controlling Vegetation Growth on Landfills. EPA-600/2- 81-164,
U.S. Environmental Protection Agency, Cincinnati, Ohio, 1981. 197 pp.
i i
Harlow, W. M. and E. S. Harrar. Textbook of Dendrology. McGraw-
Hill, New York, 1969,512 pp.
Leone, I. A., F. B. Flower, E. F.!Gilman, and J. J. Arthur. Adapting
Woody Species and Planting Techniques to Landfill Conditions."- EPA
600/2-79-128, U.S. Environmental Protection Agency, Cincinnati, Ohio
1979, 134 ipp. ;
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MAGE
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Lutton, R. J. Evaluating Cover Systems for Solid and Hazardous Waste.
~SW-867r~U.~S ,~Environmental"Protect ion~Age~hl:yT~Cinric!fo^
1 " ' ? ••(/:•:•••: 37 ••'xix':: \ '~?ATi
'GE :V_:.U8ER
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Matrecon, Inc. Lining of Waste Impoundment and Disposal Facilties. 1
SW-870. U.S. Environmental Protection Agency, Cinncinnati, Ohio* 385 pp.
1980. - ,
McRae, S. G. The Agricultural Restoration of Sand and Gravel
Quarries in Great Britain. Reclamation Review. 2: 133-141, 1979.
Pirone, P. P. Tree Maintenance. Oxford University Press, New
York, 1978. 587 pp. i
; j
Shen, T. T.' Control Techniques for Gas Emissions from Hazardous
Waste Landfills. J. of Air Pollut. Control Assoc. 31: 132-135, 1981.
Swope, G. L. Revegetation of Landfill Sites. M. S. Thesis. The
Pennsylvania State University, 1975. 98 pp.
l i
Vogel, W. G. A Guide for Revegetating Coal Mine Spoils in the
Eastern United States. Gen. Tech. NE-68. USDA, NE Forest Experiment
Station, 1981, 248,,pp. j
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
I. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
5. REPORT DATE
STANDARDIZED PROCEDURES FOR PLANTING VEGETATION ON
COMPLETED SANITARY LANDFILLS
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
Edward Gil man. Franklin Flower. Ida Leone
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Rutgers University
New Brunswick, New Jersey
10. PROGRAM ELEMENT NO.
BRD1A
08903
11. CONTRACT/GRANT NO.
CR807673
12. SPONSORING AGENCY NAME AND ADDRESS
Municipal Environmental Research Laboratory--Cin., OH
Office of Research and Development
U. S. Environmental Protection Agency
Db.tQ..., 15363
13. TYPE OF REPORT AND PERIOD COVERED
Final August iqan-.luly
14. SPONSORING AGENCY CODE
EPA/600/14
15. SU
Project Officer: Robert E. Landreth
513/684-7871
!6. ABSTRACT
A manual was developed for those charged with establishing a vegetative cover on
completed landfills. Special problems associated with growing plants on these sites
are discussed, and step-by-step procedures are given for converting a closed
landfill to a variety of end uses requiring a vegetative cover. Instructions
are given for vegetating landfills with either limited or adequate funds.
A hypothetical case of landfill conversion is also included.
17.
KEY WORDS AND DOCUMENT ANALYSIS
a.
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
13. DISTRIBUTION STAT6M6N1
19. SECURITY CLASS (This Report!
Unclassified
21. NO. OF PAGcS
RELEASE TO PUBLIC
20. SECURITY CLASS (This page/
Unclassified
22. PRICE
EPA Form 222Q-! (R«v. i-77) PREVIOUS soi TION is OBSOUSTE
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