Laserfiche WebLink
<br />OJ3J17 <br /> <br />OTHER ADDITIONAL ASPECTS OF STREAM GAGING <br /> <br />1. Reservoir Operations - Corps of Engineers and Bureau of Reclamation operations for <br />flood control, water supply, target flow maintenance and navigation support are usuaJly cooperative <br />ventures between federal project managers and state water managers. The original proposed goal and <br />metric on gaging needs for reservoirs centered on the monitoring of inflows and outflows of <br />reservoirs, However, because of the multiple drainages entering a reservoir, inflow is better <br />estimated by mass balance of the reservoir storage and estimates of evaporation and releases, <br />Outflows may be reasonably determined through hydraulic ratings of the reservoir gate openings and <br />pool level. Therefore, gaging needs actually extend beyond the vicinity of the reservoir project and <br />lie within the watershed draining to the reservoir and along the regulated stream affected by reservoir <br />operation, <br /> <br />Typically, the Corps of Engineers financially support those gages essential to the operation <br />of their reservoir projects, There is likely little threat to losing these gages because of their utility <br />in operations, such as navigation support, Federal agencies such as the Corps also support gages <br />which provide ancillary information, helpful, but not crucial to those operations, Those gages <br />present opportunities for multi-party support, particularly if the gages support state water <br />management goals as well as reservoir operations, A suggested metric to evaluate gage support of <br />this mission would be the number of gages within the HUC-IOII I watershed coverage above the <br />reservoirs and at the critical control points along the regulated streams below reservoirs governing <br />operating rules. <br /> <br />2. National Flood Insurance Program Support - Provision of flood streamflow and <br />elevations for flood management decisions in communities participating in the federal flood <br />insurance program continues to be a pressing need for adequate floodplain mapping, designation of <br />insurance rates and flood warning systems. Basic, sustained and reliable coverage to meet floodplain <br />management needs, such as mapping support, may be largely provided by the NSIP network, <br />Supplemental support to meet targeted, local needs can be directed through the Co-Op program. The <br />recommendation on the use of NSIP for flow forecasting and Co-Op program use for targeted <br />mapping needs, in no way, imparts a greater priority to forecasting and warning over mitigation, <br />planning and prevention. The intent is to maintain the base network for long term record <br />maintenance with tailored data supplements to assist provision of flow information at regional and <br />local levels, <br /> <br />This approach supports instalIation of gages as a joint federal-state-Iocal commitment for <br />priority communities with chronic flood damage claims, One cost-effective means of supporting this <br />mission would be expanding the network of crest-stage gages throughout the drainage of flood-prone <br />areas, Such gages can be correlated to an index set of continuous record stations in their region. A <br />suggested metric would be location ofa gages and crest-stage indicators on the river reaches in the <br />vicinity of state-designated high priority NFIP communities, <br />