Galbraith Drain Stream and Floodplain Restoration Project
St. Clair County,
St. Clair County Drain Commissioner
Basin Program Funds:
In the Galbraith Drain there is a problem of excess sediment loads and sedimentation caused by: the disconnection of the channel from its natural floodplain by the relocation and straightening of the natural stream and excavation of the new channel; failure of the trapezoidal channel to maintain geomorphic stability under varied flow conditions ranging from base flow to major storm events; and, flash conditions caused by an increase in impervious surface and the installation of stormwater sewer line tributaries in the watershed.
The Galbraith Drain is a County Drain in St. Clair County, Michigan that outfalls directly to Lake Huron. At the outfall the lake is listed on Michigan’s 2002, 303(d) list of impaired waters under the Clean Water Act. Metcalf Rd. Beach, located directly north of the outfall, and Keewadhin Rd. Beach, located directly south of the outfall, are both included on Michigan’s 2002, 303(d) list. The Galbraith Drain outfall is located less than 5.5.miles north of the Lake’s outfall into the St. Clair River, which is a Designated Area of Concern under the Great Lakes Water Quality Agreement between the U.S. and Canada.
The Galbraith Drain watershed encompasses approximately 3.9 square miles. The upper reaches of the watershed, west of State Road, drain rural land predominated by crop and pasture lands with some isolated forest stands. The drain and its tributaries remain in their natural floodplains although the channels are generally incised, due to the increased peak flows resulting from the conversion of the original forests to agricultural uses.
The lower half of the watershed, east of State Road, is much more developed, with industrial, commercial, and residential areas. The original stream has been removed from its natural floodplain between State Road and M-25 and relocated as a straightened, trapezoidal channel, designed to convey at least the 10-year storm event. The short reach of the drain between M-25 and Lake Huron remain in its original channel, although the majority of the channel banks in this reach have been armored by streamside residents.
In the lower half of the watershed has seen increased impervious surface areas and the installation of piped storm sewer systems on contributing lands. This along with the relocated channel (disconnected from the natural bankfull floodplain), have resulted in increases in sediment loadings even the smallest storm events.
Traditional drainage improvement projects in Michigan are funded through direct, tax assessment of landholders and can be shortsighted in an effort to minimize costs. However, for the Galbraith Drain project, the St. Clair County Drain Commissioner has received a one-time, lump sum discharge permit fee from the Detroit Water and Sewerage Department (DWSD). The DWSD has also granted a perpetual conservation easement of approximately 25 acres on the eastern extent of their property in the Galbraith Drain for the construction of a restored stream and stormwater floodplain to improve flood control and water quality conditions and the reduction of sediment transport out of the watershed.
The St. Clair County Drain Commissioner implemented a Rosgen Natural Stream Channel Design restoration on approximately 2,600 linear feet of drain channel within this conservation easement, including the excavation/construction of approximately 17 acres of bankfull stormwater floodplain, capable of capturing excess sediment loads conveyed during storm events. It is expected that the attenuation of storm flows and sediment capture within the restored stream channel and floodplain will reduce both sediment loads and erosive flow conditions not only within the restored project reach, but also downstream, in the non-restored reaches. Additionally, it is expected that the restored stream and floodplain will exhibit long-term geomorphic stability, eliminating the need for long-term maintenance of the project reach.
Approximately 2,700 linear feet (1.5 acres) of bankfull floodplain were constructed in the project reach. In the project reach and areas downstream there were four culvert replacements installed, installation of J-hook vanes, cross vanes, seeded erosion control blankets, bank rebuilding and reshaping, selective clearing and mulching, tree and shrub planting, grade control, retaining wall construction, and a beach outlet structure installation.
Two continuous-logging stage and turbidity meters (YSI Environmental model 600 Optical Monitoring System) were purchased and installed at the upstream and downstream ends of the project reach. The meters continuously recorded data at fifteen-minute intervals for the monitoring period. Data downloaded from the meters were organized into pre- and post-construction data sets and individual storm events and then used to analyze the overall effectiveness of reducing the sediment load transported by theGalbraith Drain. Additional plans are being developed for bankfull floodplain construction in areas upstream of the project reach and in nearby Huffman Drain which will be designed using results from this study.
In February 2005 preliminary findings, design strategies, and construction techniques from this project were presented at the Michigan Association of County Drain Commissioners’ (MACDC) Winter Conference; an informational booth on the project was also set up for this event. A short summary on the project was published in Pipeline magazine, which is produced by MACDC, and distributed to all members, including: drain commissioners, engineers, contractors, and vendors. A story on the floodplain construction and associated benefits to the local citizens was published in the Port Huron Times Herald.
Contact: Mr. Fred Fuller, 810-364-5369