Submitted to: Federal Interagency Hydrologic Modeling Conference
Publication Type: Proceedings
Publication Acceptance Date: October 15, 2005
Publication Date: April 3, 2006
Citation: Langendoen, E.J., Simon, A., Pollen, N.L., Williams, R.G., Lowrance, R.R. 2006. A comprehensive stream-riparian corridor model to study the impact of riparian buffers on channel and edge-of-field processes: simulation of streambank hydrology. In: Proceedings of the 3rd Federal Interagency Hydrologic Modeling Conference, April 2-6, 2006, Reno, Nevada. CDROM. Interpretive Summary: Pollutants such as nutrients and sediments, washed off agricultural fields or eroded from stream channels, may diminish the water quality of streams and rivers. The stream and the area between stream and agricultural field, the riparian zone, play an important role in the management of pollutants. The vegetation in the riparian zone is also known to reduce erosion from the streambank. The U. S. Department of Agriculture-Agricultural Research Service has been developing the computer models REMM and CONCEPTS to study the effects of riparian forests and in-stream restoration measures on water quality. These models have been integrated to provide a comprehensive tool that can be used to assess the effects of riparian buffer systems on the physical and biological integrity of a stream. The combined model has been used to study the effects of two riparian zones, consisting of trees and grass, on controlling streambank erosion of a severely eroded stream in North-Central Mississippi. Initial model results have been used to evaluate the capability of the model to accurately predict soil moisture values within the streambank. Soil moisture greatly affects streambank collapse. Simulated soil moisture values within the woody and herbaceous riparian buffers agree well with those observed. The combination of CONCEPTS and REMM is therefore a tool that can be used by state and federal agencies to assess vegetative, riparian conservation measures.
Technical Abstract: Edge-of-field buffers are a core agricultural conservation practice, and installed along the stream are a proven technology to reduce sediment loadings from both hill slope and channel bank. This paper presents ongoing research to integrate the computer models CONCEPTS and REMM, which were developed to simulate stream channel morphology and riparian ecosystem function. The integrated model has been used to study the effectiveness of hypothetical woody and herbaceous riparian buffers in controlling streambank stability of an incised stream in Mississippi. Riparian vegetation controls streambank stability through pore-water pressure (i.e., soil moisture) and root-reinforcement of the soil. The capability of the model to predict spatial and temporal variations of pore-water pressure in a streambank was tested against field data collected at Goodwin Creek, Mississippi. Model results showed that pore-water pressures are accurately predicted in the upper part of the streambank, away from the bottom boundary of the model domain. Results depended on imposed soil permeability, which is greatly affected by the development of macropores in the dry summer and fall period.