Streams are dynamic, ever-changing systems that react to modifications within their watershed. Development results in an increase in impermeable surfaces, changing the time and concentration of storm flows in streams and ephemeral tributaries. Terra Technologies engineers and biologists strive to assess current environmental conditions in order to determine the correct geometry and stream cross-section. We have assisted numerous municipalities and other landowners whose waterways have been degraded by the results of upstream development.
Fluvial geomorphology can be defined as the science of evaluating all parameters within a watershed that shape an impoundment or a stream. Natural streams are formed and maintained by hydraulic regimes that are classified as channel forming flows. Generally, channel forming flows consist of 1 to 2-year storm events. This flow range usually contains the precise flow regime that provides the balance between erosion and sedimentation, thus shaping the channel and creating stream features. Streams naturally transition to a point where the balance exists between erosion and sedimentation. When changes are made to the geomorphic conditions of the watershed, the result is typically a change in channel forming flows that result in changes to the stream features. Since man-made changes typically result in an increase to the total hydrologic volume for frequent storm events, these changes typically cause erosion throughout the stream system. The erosion will continue until the stream reaches a new balance of erosion and sedimentation based upon channel forming flows for the changed conditions.
Streams must be of sufficient geometry and cross-section to accommodate routine storm events. Flood benches must be properly sized to ensure overbank capacity. Regardless of plant type or species, a stream in moderate to severe transition will definitively remove any and all plantings. For this reason, most installations, which rely solely on willow cuttings for biological stabilization are washed away. Our biotechnical engineering solutions to stream stabilization problems incorporate many erosion control technologies from gabions to erosion control blankets. This approach, along with the installation of attractive and ecologically appropriate plant species, has been applied numerous times to stabilize streambanks in geomorphic transition.
Project Examples
Crestwood Storm Water Master Plan, Crestwood, Missouri
Platte County Watershed Study, Platte County, Missouri
Southern Oaks Streambank Stabilization, St. Charles, Missouri
Brush Creek Biotechnical Stabilization, Prairie Village/Mission Hills, Kansas
East Forest Pine Drive Bank Stabilization, Wildwood, Missouri
Plum Creek Stormwater Improvements Project, St. Peters, Missouri |
