We noticed sediment deposited on top of the bank on the upstream side of a culvert. If the sediment appears to be on top of the bank, would this still be considered a deposit?
Rockingham Planning
May 22Hello Everyone. At the training yesterday some people had expressed interest in seeing the text of our community notification letter. We keep a stack of these in our field vehicle and hand them out to members of the public when they inquire with our field crews. We found this beneficial to (1) provide them additional information and (2) avoid some of those long conversations we can get trapped in. ------------------------------------------------------------------------------ Memo To: RPC Commission Community Members and Municipal Officials and Staff From: Christian Matthews, Transportation/GIS Analyst, Rockingham Planning Commission Date: May 22, 2019 Subject: RPC Regional Stream Crossing Assessment Notification This summer and fall, Rockingham Planning Commission (RPC) is continuing a regional project aimed at identifying stream crossings (culverts and bridges) that may pose a hazard to our communities. This multi-year assessment of stream crossings in the region is intended to assist municipalities in identifying critical and hazardous culverts and bridges, particularly those susceptible to failure due to flooding or those that cut off critical evacuation routes. Using state stream crossing assessment protocol, RPC will have staff members out collecting data on state and local roads. The assessments will involve staff accessing crossings from public right of ways. The RPC shares all information collected with our member communities and works with those communities during the summer to help identify areas know to be problematic. Municipalities can use this information as a guide to prioritize those stream crossings most in need of retrofit or replacement. Along with prioritizing infrastructure modifications, results of these assessments can also be incorporated into municipal and regional hazard mitigation plans and vulnerability assessments. For more information about this project and to view this public data, please go to: http://www.rpc-nh.org/maps-and-data/data/transportation-asset-inventory-data For any questions or comments please contact Christian Matthews at (603) 658-0523 or cmatthews@rpc-nh.gov .
Tom T response- Sediment can be deposited into floodplains, and often that will occur immediately next or almost on top of the edge of the banks. We are however only interested in sediment deposition in the channel. Good Question.
As Tom explained, deposition that has occurred on the bank at high flows is not considered an upstream deposit on the streambed, but it is often (not always) indicative of deposition that is occurring on the inside of a meander bend at normal flows. So in this case, I would be sure to look in the water at this location to determine whether there is deposition within the stream. After zooming in and brightening up the photos, it looks like there is a sand bar on the inside of the meander bend.