W E T L A N D S , Vol0 Z, 198Z, pp. 179-190

WETLAND DEVELOPMENT POTENTIAL OF COAL MINE TAILINGS BASINS

Jack R. Nawrot and Scott C. Yaich, Cooperative Wildllfe Research Laboratory

Southern I11inois University--Carbondale, Illinois 62901

Abstract , Research at the Cooperative W i l d l i f e Research Laboratory has i d e n t i f i e d the environmental and economic benef i ts of u t i l i z i n g Phragmites aus t ra l ia for s t a b i l i z i n g inact ive s lu r ry impoundments. Physical and chemical factors a f fec t i ng successful vegetat ion establishrnent are con t ro l led by the maintenance of a saturated substrate which prevents py r i t e ox idat ion and acid product ion. The moist soi l zones provided by the saturated s lu r ry substrate represent a favorable root growth medium s imi la r to natural wetlands. Implementation of th is reclamation a l t e rna t i ve for the Statets abandoned mined lands has necessi tated the co l l ec t ion and propagation of other physiologically adapted native plant materials to identify species suitability and ensure availability of diverse planting stock. Acceptance of this reclamation atlernative can provide cost effective resolution of abandoned mined land problems as well as replace valuable wetlands being permanently lost through intensive agricultural/urban de ve I opme n t.

INTRODUCTION

As our natural wetlands continue to d iminish, there has developed a greater concern for t h e i r p ro tec t ion , preservat ion, res to ra t i on , enhancement, and development. In the case of development, i n te res t has recent ly focused on reclamation of waste disposal areas as wetland hab i ta t . The U.S. Army Corps of Engineers has developed wetlands e~ dredged spoi l mater ia ls {Hunt et a l . ]978, Newling 1981, Saucier et a l . 19781, and wetland hab i ta t has recent ly been establ ished on Flor ida phosphate mine c lay s e t t l i n g basins (G i lber t et a l . 1980, King et a l . 1980}. Research conducted by our Laboratory demonstrated the f e a s i b i l i t y of wetland establ ishment on inac t ive coal mine s lu r ry impoundments (Nawrot et a l . 19811. To c a p i t a l i z e on the opportuni ty of thousands of acres of s lu r ry impoundments that could be reclaimed as wetlands, in tensive research e f f o r t s have been necessary to inves- t i ga te and document the complex hydrogeochemical factors a f fec t ing vegetat ion establ ishment. This paper b r i e f l y summarizes our past and present research and plans fo r developing wetland habi ta t on mine t a i l i n g s areas.

RESULTS AND DISCUSSION

Past Research

Inventor ies of I l l i n o i s ' 200,000 acres of lands af fected by coal mining (Haynes and Klimstra 1975, Nawrot et a l , 19771 indicated a re la t i onsh ip between the occurrence, abundance, and d i s t r i b u t i o n of

]79

180 WIETI..,ANDS, Vol. Z, 1982

reedgrass (Phragmites australis), a native hydrophyte, at~d moist soil areas of mine environments, particularly slurry impoundments. The natural association of reedgrass and other perennial wetland macrophytes, including cordgrass (Spartina pectinata), cattail (Typha la t i fo l ia ) , common threesquare (Scirpus americanus), hardstem bulrush (Scirpus acutus), and other sedges (Cyperus spp.), suggested a possible adaptation or tolerance of these species to potentially phytotoxic conditions generally thought to be associated with slurry impoundments.

Site Conditions. - Slurry impoundments, disposal areas containing -28 mesh (<0.6 mm) coal processing waste, are po ten t i a l l y acid producing due to the presence of p y r i t i c materials (pr imar i ly FeS2) which can oxidize in the presence of oxygen and water to produce extremely acid condit ions (pH ~3.0, ac id i t y >500 meq H+/lOOgm). This h ighly acid environment promotes, in t u rn , mobi l izat ion of po ten t i a l l y phytotoxic s lu r ry const i tuents , e .g . , i ron, manganese, and aluminum (Brady 19745. Levels of meta l l ic sal ts therefore increase sharply resu l t ing in a high e lec t r i ca l conduct iv i ty (up to 13 mmhos/cmS. Although any one of the above condit ions could preclude vegetative growth, a c i d i f i c a t i o n of the s lu r ry environment due to pyr i te ox idat ion is the i n i t i a t i n g event. Despite the potent ial for spontaneous development of phytotoxic condit ions prevalent in most coal mine s lu r ry impoundments, wetland vegetation was iden t i f i ed as having in some cases na tu ra l l y colonized ent i re ponds or port ions of impoundments wi th in l l l i n o i s . An evaluat ion of factors af fect ing vegetation establishment on s lu r ry (Nawrot 1981) indicated the re la t ionsh ip between inherent physiological and morphological adaptation of wetland species and s ign i f i can t horizontal and ver t ica l zonation in the physical and chemical environment w i th in impoundments to be con t ro l l i ng vegetation success or f a i l u r e .

Separation and d i s t r i bu t i on of s lu r ry const i tuents by pa r t i c le size and speci f ic grav i ty during discharge resu l ts in horizontal zonation of physicochemical factors between the elevated discharge area and low- ly ing decant zone (Figure 15. Rapid sedimentation of large par t ic les and high speci f ic grav i ty p y r i t i c materials near the discharge ou t le t resul ts in deltas characterized as wel l -dra ined, elevated areas with large calcium carbonate de f i c i t s and r e l a t i v e l y low nu t r ien t status (Table I ) . Subsequent to ac i d i f i ca t i on (>18 months af ter discharge terminat ion) these areas become phytotoxic and are unsuitable for vegetative establishment. However, less dense s i l t and clay sized par t ic les are transported fa r ther by the discharge flow and deposited nearer the decant point , normally resu l t ing in a broad, r e l a t i v e l y f l a t zone overlying a shallow water table (Figure I ) . The high proport ion of s i l t and clay sized par t ic les found in th is area resul ts in a more moderate chemical environment t yp i f i ed by lower calcium carbonate de f i c i t s and higher nu t r ien t levels (Tables l and 2). In addi t ion, meandering of the discharge flow in the intermediate and low zones is associated with the deposit ion of various materials in such a way as to cause marked ver t i ca l s t r a t i f i c a t i o n in these zones. Strata of f ine sands are interspersed among other strata of s i l t s and clays, seme of which may be saturated. These saturated "slimes" layers (>60% s i l t and clay) act as an important bar r ie r to i n f i l t r a t i o n , often resu l t ing in secondary perched water tables, and serve as a nu t r ien t (Table I ) and water reservoi r . Thus, the combination of shallow water tables and/or

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presence of saturated slimes, low calcium carbonate def ic i ts , and higher nutrient status, makes the intermediate and low zones favorably suited for wetland vegetation establishment.

Investigation of a vegetated I l l i no i s impoundment identif ied a s t rat i f icat ion of phytotoxic conditions associated with the slurry surface and subsurface of vegetated areas (Table 3). The s t ra t i f i ca t ion is characterized by an unsaturated acid surface overlying a saturated circum- neutral or s l ight ly acid subsurface resulting from the prevention of pyrite oxidation in the saturated root zone which may be up to 2m below the surface (Haslam 1970). Elimination or reduction of acid production by submerging potential acid producing waste materials in a saturated zone is not unique to coal slurry impoundments. Prevention of acid production by ~anagement of saturated substrates is an effective management tool (Pionke and Rogowski 1979) and has been evaluated in uranium and iron tai l ings disposal practices (Cherry et al. 1980, Mitchell and Richards 1981). Additionally, buffering capacity contributed by calcareous materials in the saturated and unsaturated volumes aids in the main- tenance of a favorable acid-base balance by enhancing the neutralization of any acidity generated in the unsaturated zone, thereby aiding the prevention of water quality deterioration. Physical characteristics of the slurry surface l im i t opportunities for seedling establishment. In addition to being highly susceptible to sheet erosion by both wind and water, the black surface often results in surface temperatures in excess of 50-60°C. These high temperatures interacting with generally coarse-grained textures cause rapid development of excessively droughty conditions. Although seed germination is common in early spring, rapidly deteriorating surface conditions normally result in total mortality except in areas near the impounded water zone where seedling roots reach the shallow water table. Hydrophyte stands subsequently expand vegetatively from these narrow bands of i n i t i a l colonization.

The presence of wetland vegetation in what appears to be phytotoxic conditions on naturally vegetated slurry impoundments is therefore apparently related to the favorable rooting environment in the saturated subsurface zone. While seedling establishment in the unfavorable surface zone is d i f f i c u l t , reclamation to wetland habitat can be promoted through establishment of rhizomatous propagules common to many wetland species in the saturated zone (Nawrot 1981).

Vegetation Establishment. - The natural association of reedgrass and other wetland species with mine-affected environments due to their inherent physiological adaptations (rapid biomass production, high evapotranspiration rate, extensive rhizome development, and salt tolerance; Bjork 1967, Dykyjova and Kvet 1978) suggested the potential of wetland species for slurry impoundment reclamation. Subsequent research at a recently inactivated impoundment (Nawrot et al. 1981) demonstrated the appl icabi l i ty of u t i l i z ing reedgrass and other wetland species to vegetate inactive sluFry impoundments without soil cover, as currently required by federal law.

Application of the principles of vegetative propagation using rhizomes as well as understanding the important role of a saturated subsurface in preventing acid i f icat ion were instrumental in the successful reclamation demonstration of two inactive slurry areas

Nawrot and Yaich, %9ET LAND DEVEI.f)PMENT 185

Table 3. Soil parameter means (standard deviation in parentheses) for corresponding surface and deep slurry samples from a reedgrass-vegetated slurry impoundment in Macoupin County, I l l i no i s , May 1979 and May 1980 (N:39).

Variable

Surface Samples (0-6")

Mean (SD)

Deep Samples {30-36") Mean ~SD]

Soil mH 3.10 H (meq/1OOg) 10.32 Cation exchange capacity 31.03 % Base saturation

% K 0.35 % Mg 3.02 °",o Ca 57 .07 % H 28.27 % Na I I ,29

Soluble salts (mmhos/cm) 9.68 Phosphorus

Pt (Weak Bray, ppm) 38,79 I)= (Strong Bray, ppm) 60.56

Total sulfur 3.76 K (ppm) 35.87 ~g (ppm) 107.18 Ca (ppm) 3,482.95 Na (ppm) 697.97 Zn (ppm) 42.50 Mn (ppm) 26.46 Fe (ppm) 1,341.87 Cu (ppm) 3.95 B (ppm) 10.54 A1 (ppm) II0,95

(I.42) (7.o8) (I I .16)

(o.31) (1.24) (12.14) (14.82) (I0.42) (3.77)

{]6.47) (24,25) (].39) (26.77) (35.46) (1,300.17) (572.23) (40.97) (11.72) (GBs.69) (1.62) (4.25) {92.08)

6.95 (0.43)** 0.15 (0.50)**

15.37 (3,34)**

1.02 (0.28)** 4.68 (0.64)**

70.08 (6.04)** 0.49 ( I .72)**

23,75 (6.~4)** 5.85 ( I , I 0 ) * *

14.13 (4.94)** 77.49 (23.28)** 3.97 (I.16)

58.79 (14.21)** 87.31 (26.92)**

2,164.10 (550~83) *~ 819.49 (212,82)

8.38 (4.38)** 24.67 (8.92)

409,85 (197,71)** 2.37 (0.51) *" 7.87 (2.93)** 9.85 (11.37) "*

**Signi f icant ly d i f ferent at P<O.Ol.

186 WETLANDS, Vo]. Z, 1987-

total ing 27 acres. Approximately 12 exposed acres of a 20-acre impoundment were stabil ized using reedgrass rhizome cuttings planted at 18 inches and at a density of 600 cuttings/acre. Reedgrass cuttings were also ut i l ized to stabil ize more than one mile of eroded impoundment embankments.

One of our primary interests in reclaiming slurry impoundn~ents to wetlands is to provide wi ld l i fe habitat. In order to investigate the potential hazard of bioaccumulation of micronutrients such as aluminum, boron, manganese, copper, and zinc to wildTife, preliminary plant tissue analyses of root, shoot, and leaf materials were conducted; and, in most instances, concentrations of these elements were lower in plants from slurry impoundments than from non-mine related southern I l l i no i s soils (Table 4). Therefore, no increased risk of metal bioaccumulation (compared to local natural areas) resulting from con- sumption of reedgrass from slurry impoundments appeared to exist; however, these analyses wi l l be continued at other impoundments while expanding the number of micronutrients and plant species examined, and also including macroinvertebrates, another major food source for wetland wi ld l i fe .

Although cover establishment with reedgrass was extremely effec- t ive and could potential ly save mil l ions of dollars in reclamation costs for state and federal agencies and the mining industry, establish- ment of habitat diversity using other species was a reclamation goal that was also investigated. Bulrush, ca t ta i l , mi l let (Echinochloa spp.), smartweed (Polygonum spp.), rice cutgrass (Leersia oryzoides), black willow (Salix n i _ ~ ) , sycamore (Platanus occidentalis), bald cypress (Taxodium distichum), pin oak (quercus palustr is), r iver birch (Betula ni~ra), and cottonwood (Populus deltoides) were also established on a 5-acre slurry area to demonstrate that diverse wetland habitats can be developed on slurry impoundments.

Current Research

Post P.L. 95-87 Mine Sites. - Performance standards of Public Law 95-87, the federal Surface Mining Control and Reclamation Act of 1977, require any slurry impoundments active after 3 May 1978 to be covered with 4 feet of non-toxic material (soi l ) during reclamation, thus pre- cluding wetland development as a currently acceptable reclamation alternative. However, past success and the economic and environmental advantages of wetland species establishment on slurry areas has generated considerable interest in both the mining industry and regulatory agencies. To continue investigation of the reclamation alternative, our Laboratory was granted an "Experimental Practice" approved by the Secretary of the Inter ior and is actively involved in the reclamation/demonstration of a 50-acre impoundment as a wetland area. Wetland development of this site wi l l include the establishment and evaluation of 52 species in three wetland management zones, while continuing research on reedgrass in a portion of the pond. Surface water and groundwater is being monitored to assure that wetland vegetation establishment without soil cover is equally effective in meeting water quality eff luent cr i ter ia .

}q~wrot and Ya ich , W]ETI.a~.~D DEX. 'ELOPMENT 187

Table 4.

Element

Mean values of macro- and micro-nutrient concentrations, in leaf, shoot, and root materials of reedgrass established on slurry impoundments and on natural soils in southern I l l i no i s , June-August 1979.

,v , i i ,

Slurry Impoundment In=20) Natural Areas (n=l.4) Leaf Shoot Root Leaf Shoot Root

P (% dry wt) 0.2 0.I 0.I 0.2 0.I 0.2

K (% dry wt) 2.0 1.0 1.0 2.0 1.3 1.9"

Mg (% dry wt) 0.I O.D O,l 0.I 0.I 0.I

Ca (% dry wt) 0.5 0.I O.l 0.5 0.2 0.2

Na (% dry wt) O.l O.l O.l O.l 0.I O.l

Fe (ppm) 493.2 2 8 8 . 5 1,501.2 4 2 2 . 6 2 9 6 . 9 2,573.3*

AI (ppm) B5.2 61.0 484.8 370.7* 261.4" 6,100.0"

Mn (ppm) 188.2 56.2 76.5 581.3" 136.2" 392.1"

B (ppm) 21.4" 8.5* l l . l * l l .O 4.4 7.0

Cu (ppm) 7.8 5.6 7.5 17.6 9.4* 16.1"

Zn (ppm) 37.2 47.7 40.7 35.4 38.1 61.0"

*Signif ica~tlylarger (P <O.D5; t- test) than corresponding vegetation sample mean from slurry or natural area.

188 WKTLANDS, Voi. 2, 198Z

Abandoned Mined Lands. - As the optimization of habitat diversity and reclamatione--~'f-ect-~veness has been a long-term goal of our Laboratory's wetland development program, a serious need has developed for the acquisition and propagation of suitable plant materials. To ensure adequate supplies of adapted wetland species for research and reclamation demonstration purposes, a research effort has been in i t ia ted to col lect and propagate previously identi f ied species collected from inactive slurry impoundments. Physical and chemical conditions [water table elevation, potential acidi ty, neutralization potential, nutrient status, etc.) of collection sites wi l l be documented prior to transfer of plant materials to f ie ld research and demon- stration plots at a I02 acre pre-law abandoned mine site in northwestern I l l i n o i s . This research is being conducted in cooperation with the I l l i no i s Abandoned Mined Land Reclamation Council, the I l l i n o i s state agency responsible for reclamation of problem sites resulting from past unregulated mining ac t iv i t ies . Management and maintenance techniques (water level control, nutrient and neutralization amendments) wi l l be evaluated on f ie ld plots to identi fy practical approaches to species specific management. The immediate goal of the i n i t i a l f ie ld plot is to preserve and propagate potential ly adapted wetland species that could otherwise be destroyed in future soil covering of sites as might be required by federally imposed reclamation performance standards. A secondary goal is to propagate from seed and cuttings in greenhouse and f ie ld research those species that perform most successfully in f ie ld t r ia ls . The overall objective of this research wi l l be to ensure adequate supplies of ecotypically adapted plant materials to meet the needs of wetland development reclamation programs within I l l i n o i s .

SUMMARY

Dur Laboratory's recent investigations of wetland species established on coal mine slurry impoundments has demonstrated the potential of wetland development as a viable and valuable reclamation alternative for both abandoned and recently inactivated areas. Collection and propagation of diverse plant materials wi l l aid in the creation and restoration of wetlands to mitigate the loss of natural wetlands rapidly being eliminated through drainage for agricultural and urban/industrial development. A r t i f i c i a l l y created wetlands on mine slurry impoundments can provide benefits of feeding, resting, and repro- duction areas for waterfowl and other w i ld l i fe , as well as contribute to additional benefits of sediment control and water pur i f icat ion, surface and groundwater storage, and economic and technologically feasible mined land reclamation.

LITERATURE CITED

Bjork, S. 1967. Ecologic investigations of Phra~mites communis.: Studies in theoretic and applied limnology. Oslo University Press, Oslo~ Norway. 248pp.

Brady, N. C. 1974. The nature and properties of soi ls. MacMillan Publishing Co., New York. 639pp.

Nawrot and Yalch, ~ff~1.T LAND DEVELOPMENT 189

Cherry, J. A., R. J. Blackport, N. Dubrousky, R, V. Gillham, T. P. Lim, D. Murray, E. J. Reardon, and D. J. A. Smyth. 1980. Pages 353-385 in Subsurface hydrology and geochemical evolution of inactive pyr i t ic ta i l ings in the E l l io t Lake uranium d i s t r i c t , Canada. Symp. on Uranium Mill Tailings Manage., Fort Coll ins, Colorado.

Dykyjova, D. and J. Kvet. 1978. Pond l i t t o r a l ecosystems: Structure and funct ion ing. Springer-Verlag, New York. 464pp.

G i lbe r t , T. L. , T. King, L. Hord, and J. N. A l len, Jr. 1980. An assessment of wetlands establishment techniques at a Flor ida phos- phate mine s i te , Pages 245-264 in D. P. Cole, ed. Wetlands restorat ion and creation: Proc. of Seventh Ann. Conf., Tampa, Flor ida. 294pp.

Haslam, S. M. 1970. The performance of Phragmites communis, Trin. in relation to water supply. Ann. Bot. N. S. 34:147-158.

Haynes, R. J. and W. D. Klimstra. 1975. I l l i no i s lands surface mined for coal. Coop. Wildl. Res. Lab., Southern I l l i no i s Univ., Carbondale. 201pp,

Hunt , L., M. C. Landin, A. W. Ford, and B. R. Wells. 1978. Upland habitat development with dredged material: engineering and plant propagation. U.S. Army Corps of Engineers Tech. Rep. DS-78-17. 160pp.

King , T. , L. Hord, T. G i lber t , F. Montalbano I I I , and J. N. Al len, Jr . 1980. An evaluat ion of wetland habi tat establishment and w i l d l i f e ~ t i l i z a t i o n in phosphate clay se t t l i ng ponds. Pages 35-49 in D. P. Cole, ed. Wetlands restorat ion and creat ion: Proc. of Seventh Ann. Conf., Tampa, Flor ida. 294pp.

M i t che l l , E. C. and N. A. Richards. 1981. Encouraging woody plant co lonizat ion on iron mine t a i l i n g s in New York. 5th Ann. Canadian Land Reclamation Assoc., Timmons, Ontario. ]3pp.

Nawrot, J. R. 1981. S tab i l i za t ion of s lu r ry impoundments without soi l cover: factors af fect ing vegetation establishment. Pages 469-476 in Proc. of Symp~ on Surface Mining Hydrology, Sedimentology, and R~clamation. Lexington, Kentucky. December 1981.

, R. J. Haynes, P. L. Purse l l , J. R. D'Antuono, R, L. Su l l ivan, and W. D. Kl imstra. 1977. l l l i n o i s lands affected by underground mining for coal. Coop. Wi ld l . Res. Lab., Southern l l l i n o i s Univ., Carbondale. 195pp.

, M. L. Fuson, and D. M. Downing. 1981. Reedgrass and s lu r ry pond reclamation. Mining Cong. J. 67(9):23-28.

Newl ing, C. J. 1981. Monitoring of dredged material research program habi tat development s i tes . U.S. Army Corps of Engineers. Dredged Material Research Vol. D-81-1:I-8,

190 WETLANDS, Vol, 2, 1982

Pionke, H. B. and A. S. Rogowski. 1979. How effective is the deep placement of acid spoil materials. Pages 87-I04 in Symp. on Management of Toxic Wastes in Drastically Disturbed Landscapes.

Saucier, R, T., C. C. Calhoun, Jr. , R. M. Engler, T. R. Patin, and H. K. Smith. 1978. Executive overview and detailed summary. U.S. Army Corps of Engineers Tech. Rep, DS-7B-22. 189pp.