When structures are skewed to their headwall, does that affect the wingwall angles at all? Or no because it is just based off of the stream and wingwall?
See below drawing. Stream left would be 45 degrees and stream right 0?
Rockingham Planning
May 22, 2019
Hello 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 .
RPC,
You nailed it. Wingwall angle is recorded with respect to the angle between the direction of the stream flow and each wingwall. So in the diagram you included, the stream right wingwall would have an angle of 0 degrees, while stream left would be 45 degrees.
Even though the skew of the headwall makes this difficult to assess, and would make the true effects on the flow hard to determine and probably beyond the capabilities of the models we use, the simplistic answer / guideline is to ignore the slant of the headwall - which is driven by the assumption that in the majority of cases it is perpendicular to the direction of flow, and it is the wingwalls that might be weirdly angled.
Tom