Meadow Creek – Cedar Court Stream Restoration

Project Description

Meadow Creek- Cedar Court Stream Restoration

Within the proposed restoration reach, Meadow Creek was displaying lateral instability in the form of eroding banks primarily due to the amount of impervious area within the watershed associated with the residential development upstream of the project area, and the lack of vegetation along the banks. The project was proposed to restore the eroding and degraded stream to a stable stream system to provide water quality improvements and pollutant reductions (sediment, nitrogen, phosphorus) to Meadow Creek and to the Rivanna River.

A natural channel design approach was used to understand the stream morphology and hydraulic processes to create a restored stream geometry and profile that dissipates energy to reduce erosion and mitigate further downstream instability. An existing conditions hydraulic analysis was performed on the stream to identify areas with hydraulic parameters, such as velocity and shear stress, exceeded stable conditions. This information was used to define structure placement and channel slope as well as to develop the stream alignment and cross-sectional area for further hydraulic analysis of the proposed conditions. Cobble sizing was determined using the USACE Steep-Slope, Riprap design procedures, as well as the Isbash Curve for supercritical velocity vs. median grain diameter.

The stream energy was dissipated through increasing roughness, increasing flow area, reducing slopes and providing flood plain connection. The restoration design utilized both rock and log structures to provide grade control, transition steep slopes, and deflect erosive flow. The restoration involved channel grading, excavation, and select structure placement to reestablish a stable dimension, pattern and profile. Structures and bio engineering measures were used including constructed riffles, rock sills, j-hooks, toewood, soil lifts, branch layering, and live stakes. Stream banks and riparian buffers were planted with native trees, shrubs, and grasses. A new stream crossing and gravel path were added to tie the project into the existing Rivanna River Trail Network.