Upper Cedar Creek Clean Streams/319 Project
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Land Reclamation Program--Missouri Department of Natural Resources
The Missouri Land Reclamation Program (LRP) completed a cooperative reclamation project to address water quality problems associated with abandoned coal mine lands in the Cedar Creek watershed, which forms the border between Boone and Callaway counties in central Missouri . Cedar Creek is listed on the Missouri 303(d) list of impaired waters that do not meet minimum standards required under the Clean Water Act.
What was done and why?
The Upper Cedar Creek watershed was the one of the worst AML environmental problems in the Midwest . Periodic discharges of AMD and acidic sediments severely degraded water quality in Cedar Creek and resulted in numerous fish kills from 1948 until 1980. On several occasions, the entire 44 miles of stream was made lifeless. Only the flow of the Missouri River diluted the pollution impact. The entire creek bottom was mined through in several locations, accentuating flooding and water quality problems.
In the 1980's, LRP completed three projects reclaiming 706 acres in the Upper Cedar Creek watershed. The total cost was $4.7 million. The final of the three was the 404-acre Upper Cedar Creek (UCC) project, completed in 1990 at a cost of $2.3 million. Reclamation improved water quality in Cedar Creek and reduced the likelihood of mine-related fishkills .
Six passive treatment wetlands were constructed and 2700 linear feet of eroding stream banks were repaired in 2001-2002 to control acid mine drainage (AMD) in Cedar Creek. Preliminary water quality data indicate a significant decrease in acidity, sulfates and dissolved metals in Cedar Creek following wetland construction and stream bank repairs.
Who was involved?
Total construction cost of the wetland and stream bank project in 2001-2002 was $ 354,094. LRP received money from two alternative funding sources to control AMD problems in the Cedar Creek watershed. The US Office of Surface Mining (OSM) contributed $204,094 under their Abandoned Mine Land (AML) Clean Streams Initiative. These funds are supplemental to annual AML Fund grants and can only be used to remediate AML water quality problems. DNR's Water Pollution Control Program (WPCP) awarded $150,000 of the Environmental Protection Agency's (EPA) water pollution control funds through a 319 grant.
LRP entered an agreement with the USGS Midwest Science Center to document Cedar Creek ecosystem recovery. Field work was completed in 2002, and a detailed report will be available in 2003. Other important cooperative project partners include: WPCP, Boone County Soil Water Conservation District, OSM, EPA, USDA Natural Resource Conservation Service, Missouri Department of Conservation and the Columbia Audubon Society. All work took place on private property with landowner approval. LRP appreciates the statewide citizen and landowner support we have received for this project.
UCC Clean Steams/319
Improving Cedar Creek water quality is the main emphasis of the UCC Clean Streams/319 project. The overburden remains extremely acid-forming with high concentrations of pyrite. Acid-forming minespoil and coal waste generated enormous water quality problems. Large acid seeps continued to plague the project after the initial reclamation was completed in 1990. Flooding in the 1990's damaged significant portions of stream banks at UCC. Additional acid-forming materials were exposed and more sediments entered Cedar Creek. The Clean Streams/319 project repaired the damage, remediated the acid seeps and minimized future flooding impacts.
A list of completed and proposed work as of October 1, 2002:
• Six wetlands and alkaline producing cells were constructed to treat AMD by adding alkalinity, and removing dissolved metals and sulfates.
• Sixteen stream bank areas totaling 2700 linear feet were repaired to mitigate acid seeps, remove coal waste, repair previous flood damage and restore riparian environmental quality. Two stream banks were repaired 1997 and 1999. Native trees and shrubs are being planted to restore riparian zones.
• Four acid ponds were amended and neutralized.
• Sixty-six acres were amended and seeded in 1997 and 2000 with native grasses for erosion control and wildlife habitat. Additional native grass plantings are intended in the coming years.
• Approximately 200,000 trees have been planted since 1991. Additional plantings are intended in the coming years.
Passive Treatment Wetlands
Six AMD treatment wetlands were constructed at the Cedar Creek Clean Streams project site. Constructed wetlands add alkalinity, increase pH, and remove dissolved sulfates and metals from the mine drainage. Wetlands 1 and 2 each contain Vertical Flow Wetlands (VFW). These wetlands consist of a "layer cake" of limestone rock, compost, and standing water. Water is forced through the layers into perforated PVC pipes on the bottom of the wetland. Impounded water in the wetland creates the hydraulic head necessary to push the water into the pipes. As water moves through the compost, dissolved oxygen is removed by the decomposition of organic compost, and ferric iron (Fe 3+ ) is reduced to ferrous iron (Fe 2+ ) in the compost layer. Sulfates and additional dissolved metals such as aluminum are removed in this process as well. A portion of the limestone rock immediately neutralizes acidity in the mine drainage. More importantly, the calcium carbonate in the limestone is readily solubilized in the oxygen-poor water. Excess alkalinity in the treated drainage flows downstream neutralizing additional inputs of acidity that may enter the stream along the way. This process "buffers" the stream from periodic, rapid water quality fluctuations that could harm aquatic organisms and ecosystem stability.
The Cedar Creek vertical flow wetlands are approximately 35 feet wide, 100 feet long and 4 feet deep. Water depths range from 1 to 2.5 feet. The "cake" layers are comprised of 1.5 feet of organic compost, 2 feet of 3-5 inch diameter limestone rocks, and 6 inches of hay or straw on the bottom of the VFW cell. Five tons of agricultural limestone, the equivalent of over one ton of pure, reactive calcium carbonate, was mixed into the compost to increase the amount of alkaline-producing material in each VFW cell. Each cell contains 324 tons of 3-5 inch limestone rock and 258 cubic yards of compost designed to add 200 mg of alkalinity for every liter of flow. At this rate, the limestone in the VFW will be consumed at a rate of 21.9 tons per year.
Anaerobic, compost-filled wetlands enclose the VFW cells. These are very similar to the VFW cells except that water is not pulled through a piping system. Mine drainage slowly moves through the layer cake of limestone and compost as horizontal flow as opposed to the vertical flow created by the VFW's hydraulic head. Compost provides a rich substrate for sulfate-consuming bacteria. Sulfates and metals are removed, and alkalinity is increased in a similar to the VFW, but at a slower rate.
Six anaerobic, compost wetlands called OLA ( O rganic matter, L imestone rock and A g lime) cells were constructed at the Upper Cedar Creek project. Two are free standing and not connected to the VFW. These OLA cells were located in areas where the water quality was not as poor as that near the VFW. All OLA cells were excavated 2 feet below proposed water elevation of each cell. One foot of standing water was placed over four inches of limestone rock and eight inches of a mixture of compost and Ag lime in the OLA cells.
Calculating the life of treatment wetlands can be difficult. Variation in flow and water quality over the course of many years makes it very difficult to model and predict the rates at which alkalinity and organic matter are consumed. LRP estimates that the functional life of the wetlands and VFW should easily exceed ten years.
Two anaerobic wetlands built in 2002 are similar in design and size to Wetland 4. Expected functional life should exceed ten years. These wetlands are treating several acid seeps downstream of Wetland 1 and should mitigate flow of most significant seeps on the Boone County side of Cedar Creek. Additional native grass seeding and tree planting will continue to promote long-term stream bank and wetland stability.
Construction included six wetlands (shown in blue) and the repair of twelve stream bank areas mitigating acid mine drainage in the Upper Cedar Creek watershed.
Contacts
T. Kevin O'Donnell, Department of Fisheries and Wildlife University of Missouri-Columbia (573) 886-5510 tkot24@mizzou.edu David L. Galat, U. S. Geological Survey, Cooperative Research Units, Department of Fisheries & Wildlife Sciences, University of Missouri (573) 882-9426 galatd@missouri.edu