Ecological Restoration and Mitigation Banking
A CLEAR CHOICE GMC’s Environmental Department has over 120 years of combined experience performing wetland and stream permitting and restoration, mitigation planning, and establishing mitigation banks in the southeast. Our diverse team of engineers, ecologists, biologists, chemists, geologists, and survey specialists allows us to provide a unique, interdisciplinary approach to mitigation. We utilize various stream assessment and design methods, including Rosgen stream classification, ecological assessment protocols, and natural channel design. Collectively, our team has designed over 160,000 linear feet of stream in multiple physiographic provinces, as well as in both urban and rural environments. GMC has worked with both Federal and State agencies across the southeast to implement quality mitigation in the form of mitigation banks, in-lieu fee programs, and permittee-responsible mitigation.
SERVICES
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Banks Established Assessment Areas Restoration Sites
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Wetland Delineations Wetland Permitting Wetland Mitigation Mitigation Banking Stream Restoration Design and Construction Phase I Environmental Site Assessments Phase II Environmental Site Assessments Environmental Assessments Environmental Impact Documents and Statements Stormwater Permitting and Compliance Endangered and Threatened Species Survey Flood Plain Studies Detention Pond Design Air Permitting Landfill Design and Permitting Sourcewater Protection Plans Hydrogeologic Evaluations Brownfield Projects Underground Storage Tank Closure Underground Storage Tank Investigations Geographical Information System (GIS)
Selma Dixon Mitigation Bank ALDOT SINGLE USER MITIGATION BANK DALLAS COUNTY, ALABAMA
GMC established a 93-acre site in Dallas County, Alabama as a single-user stream and wetland mitigation bank for the Alabama Department of Transportation (ALDOT). The site had previously been used for agriculture and silviculture activities. These activities resulted in a loss of wildlife habitat and unstable stream banks that were actively eroding, causing sediment loading to the Cahaba River. As mitigation bank sponsor, GMC is leading the efforts to restore the property to its natural bottomland hardwood wetland system. Restoration activities include re-establishing the natural pattern, profile, and dimension of the streams to decrease erosion and sediment loading, as well as removing invasive species and planting native bottomland hardwood species to re-establish wildlife habitat and enhance wetland function. GMC is restoring over 5,000 linear feet of stream and its associated riparian buffer, resulting in improved water quality in the Cahaba River watershed. The Freshwater Land Trust, in partnership with GMC, established a conservation easement to include the Selma Dixon Mitigation Bank in February of 2018.
Bucksnort Mitigation Bank ALDOT SINGLE USER MITIGATION BANK TRAFFORD, ALABAMA
GMC is currently establishing a 260-acre site in Trafford, Alabama as a single client user wetland and stream mitigation bank for the Alabama Department of Transportation (ALDOT). Mitigation activities will include the enhancement and preservation of 20 acres of wetlands and 240 acres of riparian buffers along 25,000 linear feet of perennial stream, 7,000 linear feet of intermittent stream, and 13,000 linear feet of ephemeral stream. The existing riparian buffers are wetland bottomland hardwood forests that have been significantly disturbed by silviculture practices. Greater than 25% of these buffers are made up of exotic, invasive species including Chinese privet, mimosa, and Japanese clovers. GMC’s objectives for riparian buffer enhancement are to encourage and support bottomland and upland hardwood systems of high ecological function and native species diversity. To achieve these objectives, all silviculture activities will be discontinued, previously planted pines and nonnative vegetation will be removed, and native vegetation will be planted. These activities will help to restore and enhance the natural aquatic and ecological functions of the watershed.
Above: Bucksnort Mitigation Bank (Before)
Cahaba River Mitigation Bank BIBB COUNTY, ALABAMA
In 2010, GMC created a private wetland and stream mitigation bank to serve compensatory mitigation needs in the Cahaba River watershed for U.S. Army Corps of Engineer permits. The property had been used for farming and cattle operations for 50 years, which had severely impacted the streams and wetlands on-site. Across the 800-acre site, GMC removed culverts, replaced bridges, restored perennial streams using natural channel design, performed exotic species control, and planted native tree species within wetland areas and riparian buffers. These restoration activities re-established natural stream and wetland hydrology, enhanced wetland function, increased native species density and diversity, and restored proper pattern, profile, and dimension to the streams. As part of the Cahaba River Mitigation Bank establishment, the multiple streams on-site, Haysop Creek, and 51,000 linear feet of the Cahaba River were placed in a conservation easement in order to protect the public benefits of high water quality and wildlife habitat.
• Natural channel design and stream restoration, providing more natural pattern, profile, and dimension. • Wetland Restoration including native tree plantings and hydrologic improvements. • Plant buffers with native bottomland hardwood trees. • Exotic species control of Chinese privet.
MidCreek Mitigation Bank BARBOUR COUNTY, ALABAMA
Midcreeks Mitigation Bank is a 730-acre site located just outside of Eufaula, Alabama that was previously used for timber farming and agriculture. Before restoration, the wetlands and streams on-site were severely impacted by prior land management activities. In an effort to decrease property inundation, streams had been straight-lined and numerous ditches dug to expedite drainage. Although these practices led to a higher timber yield at the time, they also resulted in incised stream channels with actively-eroding, unstable banks. Sediment and agricultural pollutants were being rapidly transported downstream, negatively affecting water quality. Additionally, native wildlife and plant species habitat had been eliminated by the conversion of the land from a bottomland hardwood forest to row crops and pine stands. GMC is in the process of restoring, enhancing, and preserving the ecological resources at Midcreeks. Wetland restoration activities include clearing planted pines, filling ditches (reestablishing the natural hydrology), and planting native bottomland hardwood tree species. Stream restoration activities include the utilization of natural channel design for channel reconstruction and the planting of riparian buffers, thereby increasing stability, decreasing erosion, minimizing sediment loading to the system, and improving habitat. These restoration activities also promote the natural retention of water on site, thus enhancing wetland function and improving downstream water quality. To date, GMC has planted riparian buffers along 6,357 linear feet of stream, restored 225.58 acres of wetland, and restored 3,400 linear feet of stream at Midcreeks.
Above: Saugahatchee Stream Restoration (After) Right: Saugahatchee Stream Restoration (Before)
Saugahatchee Tributaries Stream Restoration AUBURN, ALABAMA
GMC provided design and construction services for two tributary restoration projects at this site. The site included over 1,000 linear feet of stream that had been straight-lined, resulting in an incised channel that was disconnected from its floodplain. The riparian buffer along the stream was overrun with invasive species that were out-competing native species for resources. Reference reach data was collected from stable, functioning streams in the nearby Tuskegee National Forest and used to determine target design channel dimensions such as bank height ratio, bankfull depth, and width-to-depth ratio. GMC utilized both Priority 1 and 2 natural channel design restoration techniques to reestablish floodplain connectivity, allowing the stream to deposit sediment and nutrient loads on the floodplain while dissipating erosive flood energy. GMC restored the main tributary to Saugahatchee Creek as permittee-responsible offsite mitigation. GMC also united numerous public and private stakeholders to assist in restoring a smaller tributary on the property with EPA Section 319 funding.
D’Olive Stream Restoration DAPHNE, ALABAMA
The D’Olive Creek restoration reach extends from Interstate 10 to its downstream terminus at Highway 90 in Daphne, Alabama. The creek’s watershed drains part of the eastern shore of Mobile Bay, including parts of Spanish Fort and Daphne. The watershed has been experiencing rapid residential and commercial development in previously forested and agricultural land use areas. These developments were increasing the amount of impervious surfaces, thereby increasing the volume, velocity, and carrying capacity of runoff feeding D’Olive Creek. The creek was experiencing erosion, stream channel degradation, and causing extensive sediment loading to the watershed and ultimately Mobile Bay. An estimated 1,700 tons of sediment per year was eroding from the streambanks in the project reach. The purpose of this project was to address the instability of the creek and reduce sediment loading. GMC’s objectives were to use natural channel design techniques to create a stable, self-sustaining system that could withstand applied shear stresses with minimal erosion and would provide natural habitat for the riparian ecological community while maintaining the functionality of the culverts at I-10. Reference stream data and historical flow data was used to design the channel with proper dimension, pattern, and profile to handle anticipated flows. In-stream structures and the planting of native vegetation were used to stabilize the channel and banks to further minimize erosion and sediment loading. GMC provided geomorphic assessment, design, construction management, monitoring, and adaptive management services for this project.
Broadview Mitigation Bank MASON COUNTY, ALABAMA
The Broadview Mitigation Bank site was previously used for cattle operations. Prior land management activities included channelizing streams, using pesticides and herbicides, and allowing cattle grazing in and around the streams. These activities resulted in impaired stream channels with eroding banks, as well as impaired water quality from livestock waste, sediment loading, and polluted surface runoff. Additionally, upstream agricultural land use utilizing row crops increased the amount and velocity of flow that the site received, worsening stream bank erosion and sediment loading. More than three miles of stream were restored using natural channel design techniques. The newly constructed streams have re-established floodplain connectivity, creating a stable system that can withstand anticipated storm events while experiencing minimal erosion. Additionally, all cattle and agriculture operations within the bank boundary were discontinued. GMC also performed exotic species control to enhance the on-site wetlands and riparian buffers. The buffers were planted with native bottomland hardwood trees. These mitigation actions have minimized erosion and sediment loading, enhanced on-site and downstream water quality, and restored the natural ecological functions of the wetland and stream systems.
Tiawasee Stream Restoration DAPHNE, ALABAMA
GMC restored approximately 1,300 linear feet of Tiawasee Creek in Daphne, Alabama. Prior to restoration, the creek was eroding in an upstream trajectory, threatening the braided wetland system at its headwaters and contributing high volumes of sediment to the watershed. The objectives of this project were to address the instability of the creek, reduce sediment loading, and prevent the loss of wetland functionality upstream of the project reach. GMC utilized natural channel design techniques to restore the stream and floodplain to a stable, functioning system with proper channel dimension, pattern, and profile. The design incorporated reference stream data, historical flow data, in-stream structures, and native vegetation planting to create a system capable of withstanding anticipated flows and associated shear stresses. GMC’s restoration services for this project included geomorphic stream assessment, watershed assessment, cost estimation, design and engineering analysis, hydrologic and hydraulic modeling, plan production, permitting, construction oversight, monitoring, and adaptive management as the project progressed. The team also provided bid document preparation and grant oversight.
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CONTACT GMC
JOF MEHAFFEY, PWS Executive Vice President, Environmental T (615) 333-7200 jof.mehaffey@gmcnetwork.com
LEE WALTERS, PWS Regional Vice President, Environmental T (251) 460-4006 lee.walters@gmcnetwork.com
STUART BLACKWELL, PWS Mitigation Bank Manager - North T (205) 879-4462 stuart.blackwell@gmcnetwork.com
ROB CARLTON, PWS Mitigation Bank Manager - South T (334) 271-3200 rob.carlton@gmcnetwork.com
GARY BROWN, CPESC, LEED GA Mitigation Bank Manager - East T (864) 527-0460 gary.brown@gmcnetwork.com