WI 18-116 - Irrigation Diversion and Sediment Transport Improvement

The O&C Ditch Company's irrigation diversion structure utilizes a reinforced concrete dam structure that was rebuilt after sustaining serious damage during the 2013 flood.  It diverts up to a total of 8.12 cfs to the south under an 1861 senior appropriation with an additional 1875 junior appropriation. The ditch company's decree is the most senior on the Little Thompson River and one of the most senior on the South Platte River.  The diversion is located in a low-gradient stretch of the river with a very heavy sediment load upstream of the diversion. An existing head gate and measuring flume exist in close proximity to the diversion structure.  Incorporated with the ditch company's measuring flume is an additional head gate and measuring flume which allows water to be bypassed and measured around the diversion structure.  This entire structure was built after the 2013 flood and is in good working order.  However, it is prone to being overwhelmed with sediment during the irrigation season.  As a result, the flow measurement is inconsistent and cannot be relied upon.
The B&L Ditch Company's irrigation diversion structure utilizes a reinforced concrete dam structure that was partially rebuilt after suffering damage during the 2013 flood.  It diverts up to 85.0 cfs to the south under several senior decrees with appropriation dates in 1875, 1877 and 1890.  It can divert a total of 400.0 cfs under more junior decrees with appropriation dates of 1904 and 1987. The diversion stores irrigation water in the Ish Reservoir that is located south of Berthoud and just east of 287.  The diversion is located in a low-gradient stretch of the river with very heavy sediment load upstream of the diversion. An existing head gate and measuring flume exist in close proximity to the diversion structure.  An additional head gate and measuring flume which allows water to be bypassed and measured around the diversion structure is also located just off the inlet ditch.  The measuring flumes are in good working order.  However, they are prone to being overwhelmed with sediment during the irrigation season.  As a result, the flow measurement is inconsistent and cannot be relied upon.