Mitigation Management sought to implement the mitigation plan developed for the Rocky Creek Mitigation Bank. This plan was developed in accordance with the following regulatory guidance/rules:
- Standard Operating Procedure, Compensatory Mitigation [March 2004] (“2004 SOP”),
- Compensatory Mitigation for Losses of Aquatic Resources [33 CFR Part 332, 73 FR 19594-19705, April 10, 2008] and [40 CFR Part 230] (“2008 Final Rule”).
The Rocky Creek Mitigation Bank (RCMB) was authorized as a commercial mitigation bank to provide stream mitigation credits for sale to public and private permittees that received a Section 404 permit authorization from the U.S. Army Corps of Engineers (USACE) and a Section 401 certification from the Georgia Environmental Protection Division (GEPD) located within the designated RCMB service area. The RCMB was also utilized by public and private permittees that received buffer variances from the GEPD.
The RCMB is approximately 39 acres in Jasper County, Georgia. The RCMB is within the Upper Ocmulgee River watershed; Hydrologic Unit Code (HUC) 03070103.
The site was historically used for agriculture practices. This historic trend continues, with the RCMB’s watershed consisting primarily of agricultural and silvicultural land use. These practices greatly contributed to the degradation of the stream system by creating in-channel vertical and lateral instability through anthropogenic manipulation, thereby limiting the system’s ability to effectively convey the bankfull flow. The existing incised and entrenched channels did not allow for any floodplain relief, thus creating high-energy flows with significant erosive potential, while the lack of deep-rooted vegetation (pasture/field conditions) limited bank protection.
As part of the proposed RCMB, streams were stabilized and restored, and riparian buffers were restored and protected. Reductions in sediment was achieved by restoring ditched and channelized streams to their proper function, and by reconnecting and enhancing the channels that existed at the time. Reductions in nutrients were achieved through the restoration of riparian buffers that filter runoff and promote nutrient uptake, and through the restoration and enhancement of adjacent riparian wetland areas that promote denitrification and increased filtration. The riparian wetland areas were further enhanced by the backfilling of a ditch network that was draining the areas of its historic hydrology.
The goals of the RCMB were to improve the resource functions of Rocky Creek and one tributary through natural channel design as they descend through valleys and adjacent wetland systems. Specifically, the RCMB:
Stream restoration component:
- Increased diversity of benthic organisms
- Increased diversity of shredder taxa
- Increased diversity of clinger taxa
- Increased habitat for shredder taxa
- Increased habitat for clinger taxa
- Increased diversity of fish species
- Increased abundance of fish species
- Increased pool habitat for Lepomis sp.
- Improved vegetative diversity in the riparian buffer
- Created varied vegetative stratums
- Decreased baseflow turbidity
- Decreased bank erosion rates
- Restored floodplain connectivity
- Decreased in-channel shear stress
- Increased median particle size
Wetland restoration component:
- Restored historic hydrology
- Increased function as defined by HGM standards
- Increased groundwater recharge
- Improved vegetative diversity
- Diversified vegetative stratums
- Increased hydrophytic vegetation
- Created stable habitat heterogeneity
Ultimately, the organization was responsible for implementing the final restoration plan. At the time, the restoration plan (see attached for details) was anticipated to include:
- ~ 4,082 LF of priority 1/2 stream channel development
- 18 rock vanes
- 31 woody riffles
- 19 toewood structures
- ~ 19,287 cubic yards of grading
- ~ 494 cubic yards of excess material to be hauled from site for disposal
- Backfilling of old abandoned channels in their entirety
- Topsoil stockpiling and replacement on cut areas