Evaluating a hydrological flood routing function for implementation into a hydrological energy model

Sammanfattning: In 2011 the Bonneville Power Administration (BPA) released new data for the streamflow in the Columbia River. This extends the previous database record (1928-1999) to include the last nine years (1999-2008). Thomson Reuters Point Carbon are using this database to apply their proprietary hydrological HBV-type energy model in the Columbia River and therefore need a complete understanding of the data and the methods behind them. This master thesis aims at understanding the different aspects of hydrological routing in general and more specifically in the Columbia River and to develop a hydrological routing function. The routing function should be simple yet robust and applicable in areas where data is scarce. A routing routine based on the ”cascade of reservoir” routing technique, similar to the one used in the SSARR model, is developed. The routine is verified by using the parameter values and the average daily unregulated routed flow (ARF) data provided by the BPA. A methodology for parameter estimation, in Columbia River and in the general case, is developed. For the general case where the parameters are unknown, two alternative parameters estimation methods are presented, one method that can be used with a scarce amount of data and a second one for when additional data is available. The overall effects of routing in the Columbia River catchment are relatively small. There are apparent lag times of around 2-3 days and noticeable flow attenuation between the dams Mica (headwaters) and The Dalles (distance 1300 km). Most of the water in the Columbia River enters as tributaries or local inflows along the flow path; this reduces the effects of routing at The Dalles. The reasonableness of the routing routine is evaluated with the Muskingum method. The Muskingum parameter values are calibrated to fit the effects of routing between Mica and The Dalles, produced by the routing routine. The calibrated Muskingum parameters are evaluated and considered to be reasonable.