East Branch Winters Run

Rahl Wetland Creation and Stream Restoration

East Branch Winters Run, Harford County, Maryland

Sponsor
Maryland State Highway Administration.

Project Description: Stream Restoration
The existing channel had been channelized and straightened, causing high bank erosion rates, mid-channel bar creation, and extreme lateral instability. The design objective was to give the East Branch Winters Run an overall stream geometry more consistent with the historic meander pattern, improve the streams interaction with its floodplain, and to improve fisheries habitat. In order to accomplish these goals the design calls for an increase the stream’s sinuosity and meander length, creating a more defined thalweg channel, and stabilizing the stream banks.

Currently the streambanks are four feet high, vertical, and have a high bank erosion potential. The streambanks are to be regraded to an average of 3:1 slopes in straight reaches and on the outside of meanders, and they are to be regraded to an average of 10:1 slopes on the inside of meanders to create point bar areas. Boulder vane and root wads, placed at 30* angle to the bank in an upstream direction, will provide structural integrity and velocity deflection at critical locations along the concave banks.

Cross vane weirs are also to be installed for grade control and to properly direct low flow, bankfull, and flood flows into meanders. Sod mats and willow transplants will placed on the banks and compacted to immediately create a fully natural and vegetated streambank.

Project Description: Wetland Creation

     Along with the restoration of the East Branch Winters Run 7.19 acres of palustrine forested wetlands are to be created in the surrounding floodplain. There are three factors taken into account in order to obtain a design that will yield adequate hydrology for the proposed wetlands: groundwater elevations, surface water, and the stream/floodplain interface. The groundwater information obtained over the two and a half year monitoring period is critical for determining the final wetland grades to intercept groundwater hydrology.

     Wetland grades were determined so that hydrology will be consistent throughout the wetland areas. While groundwater will be an important component of hydrology for the created wetlands, surface water from the unnamed tributaries to the East Branch Winter’s Run will be spread throughout certain wetland areas to add additional hydrology. This additional water will be critical in sustaining wet conditions during dry periods like the one seen in the summer and fall of 2001 and 2002.

     In addition, the restoration of the East Branch Winters Run will result in an increase in the stream’s thalweg profile. The effect of the increase in the stream’s thalweg on the wetland hydrology adjacent to the stream will be two fold. The higher thalweg elevation will improve the interaction between the East Branch Winter’s Run and its floodplain. This will further increase the residence time of the groundwater in floodplain, reducing the drastic fluctuations seen in groundwater levels next to the stream as a result of drainage, which will result in higher groundwater levels in the wetland areas.

Construction

The stream restoration portion of the project was designed by Scott McGill, and the wetland construction was designed by Jim Morris, both principals of Ecotone, Inc. Both project components were constructed by Environmental Quality Resources Inc.

Cost

Design: $135,000
Construction: $615,000

Phases of the Project:
	The site prior to construction was a degraded floodplain pasture.	The stream had been channelized in the early 1980's. The channelization initiated accelerated bank erosion.
	Agoo view of the channelized stream prior to construction.	A stable reference reach on West Branch Winter's Run was surveyed.
	Riprain area prior to construction.	One of the upper wetland cells being excavated.
	Wetland cell ready for topsoil.	Wetland cell after completion of grading.
	Wetland cell ready for seeding and planting.	Excavation of the new stream channel.
	Construction of a cross vane in the new relocated channel.	Construction of the new channel.
	A freshly graded and topsoiled wetland cell.	Completed stream about 1 month after completion.
	Completed stream with root wad shown in foreground.	New stream channel showing a boulder vane alternating with a root wad along the outer meander bend.
	Wetland cell 2 months after completion.	Wetland cell 2 months after completion.
	New stream channel several weeks after it was completed.	New stream showing boulder vane and sodding.
	A rock vane and cross vane weir.	A cross vane weir along the new relocated stream.
	New channel.	New channel with a rock vane in the foreground.