Hi all. I live in pretty flat country in the panhandle of Texas. Generally our slopes are 2% or less. When reading about dam construction in the Designer's Manual (pg. 159 on the bottom) there are illustrations of contour dams in flat country that look like trapezoids from aerial illustrations. With a dam constructed this way, is the keyway excavated and compacted just on the lower wall, or are the sides also excavated and compacted making a U shaped keyway? Does anyone know of illustrations or photographs of the construction of such dams? We're typically very flat and often very dry (avg. rainfall 480 mm/year, with variations from 127 mm like last year to 1016 mm in our 100 year flood like in 1940) so I feel like we need more small dams on any property we can build them on. We have dark red high clay soils, so having enough clay content shouldn't be an issue. Any advice would be fantastic!