Gambles Mill Eco-Corridor Restoration

The Little Westham Creek Stream Restoration Project is located on the University of Richmond property, in the City of Richmond, just a mile from the James River. The restoration site includes Little Westham Creek and three of its tributaries. The main restoration reach has a drainage area of approximately three square miles.

Construction activities began in March 2019 and were completed in September 2019. The post construction survey was completed in December 2019. The site was planted March 2020.

The restoration activities included:

• Construction of a small, main channel through a wide, well-vegetated floodplain
• Installation of riffles, pools and wood habitat structures along the main channel
• Installation of stone steps and pools along the tributaries
• Seeding and planting of native species throughout the stream banks, floodplain and uplands

The main channel of Little Westham Creek had high rates of erosion along both banks, particularly where the channel had migrated into the valley walls. The channel was oversized and downcut significantly. The tributaries were incised to meet the bed elevation of the mainstem.

The restoration realigned and raised the mainstem channel and cut a new floodplain with a small baseflow channel to increase overbank flow frequency. Cobble and logs were used to create riffles, with pools in each meander bend. Woody materials were used to provide stability and habitat in the meander pools and within the floodplain. The tributaries were stabilized vertically with stone steps which create stability and pool habitat.

With a little help from some four-legged friends, more than 100 goats were brought onto campus to help remove invasive vegetation. Read about the goats' visit  here .

Post invasive removal, the stream banks, floodplain, and disturbed upland were seeded and planted with native herbaceous and woody plant materials. In total, 3.68 acres of floodplain wetland and 3,000+ linear feet of stream bank were seeded and planted.

The main stream channel has a 3.0+ square mile urban watershed that has flash flood events during storms. When more than 0.25 to 0.5 inches of rain falls on the watershed, the flash flows breach out onto Little Westham Creek's floodplain where the vegetation helps to slow the velocity and capture pollutants. This approach of managing urban runoff in the floodplain (instead of by building streams with heavy stone structures) is much more ecologically beneficial and supports wetland formation in the floodplain, which improves both wildlife habitat and water quality.

Click play on the video below to watch a time lapse of a flash flood event in Little Westham Creek.

During the initial field assessments, RES recognized that the degraded stream showed the classic indicators of historical impacts from being dammed for water power. The stream channel was cutting into the western valley slope instead of being centered in the floodplain. The stream banks were 4-6 feet tall and composed of fine sediment, which were eroding. During routine storm events, the stream could not breach out over its floodplain because the channel was too deep, leading to even more erosion. We knew that this stream had been dammed historically but no maps showed dams in this location. Fortunately, an archeologist walked the site and found this remnant of the dam protruding from the valley wall. There was also a very odd 10-foot tall mound in the floodplain that was recognized as a fragment of the dam. Originally, this earthen dam spanned the entire valley, ponding water upstream for several thousand feet about 10 feet deep. Sediment collected behind the dam as water came down the stream and settled in the pond. The dam was likely breached during a big storm and the stream cut down into that soft, deposited sediment known as “legacy sediments.” This is what caused the steep banks we saw before restoration. Once the stream cut into the legacy sediments, it then started to work back and forth to build a new floodplain by eroding away the tall banks during storm events. That loose sediment was transported downstream to the James River and ultimately to the Chesapeake Bay. The stream restoration efforts removed these legacy sediments and gave the stream access to its floodplain, creating a stream that is much like what might have been here prior to European colonization.

Use the map below to view some of the featured points of interest along the stream restoration project.

RES is providing annual monitoring of the stream as required by various regulatory agencies, including assessment of channel stability and vegetation. Maintenance will be performed when determined by monitoring as required for the long-term success of the project. In addition to the regulatory monitoring, RES has been conducting surveys of the fish and aquatic bugs present in the stream before and after restoration. The surveys indicate that the fish community is shifting from one dominated by pond species to one dominated by fish adapted to living in fast flowing streams. RES has documented that fish typical of the James River have migrated upstream into the restored stream.

In addition to the continued monitoring efforts that RES is performing, the University of Richmond is conducting a wide range of research on the animals using the eco-corridor and the condition of the stream. Partnered Virginia Commonwealth University is also conducting water quality studies of the stream.