Laserfiche WebLink
structures for streamflow monitoring, to recommending that the State continue on with the <br />existing system until ongoing investigations by the USGS and others are further advanced. <br />3.2.3.4 Maintenance of New Gages. DWR staff are responsible for the general <br />maintenance and operation of many of the existing streamflow gages and diversion satellite <br />monitoring systems in Division 1. This responsibility would continue with the twelve new <br />diversion satellite monitoring systems and the replacement streamflow gages at the three <br />candidate rated controlled sections. At current staffing levels, up to two additional standard <br />streamflow gages can be maintained by Division 1. Beyond the two gages, however, the <br />additional new standard streamflow gages would be rated, operated and maintained under the <br />SPDSS for the duration of the SPDSS implementation program. After SPDSS implementation, <br />responsibility for the gages would be turned over to the State. <br />3.2.3.5 Point Flow Stream Gaging. A point flow module or gain/loss module would be <br />an integral part of the surface water planning tool. Additional stream gaging required for the <br />gain/loss studies recommended in the SB 96-74 report is included in Table 3-1. The SB 96-74 <br />recommendations include the measurement of gains and losses in stream base flow in valleys <br />with thin alluvium overlying the Denver Basin aquifer, with measurements done twice per year <br />over atwo-year period. This information can be used in coordination with the groundwater <br />modeling component of the SPDSS to evaluate the accuracy and validity of the Denver Basin <br />and Overlying Alluvium Region groundwater model. Approximately 25 gaging sites will be <br />selected in coordination with the groundwater modeling team. Information to be collected from <br />the field and available topographic mapping will include flow, streambed slope, and channel <br />width. <br />Point flow gaging on the mainstem of the lower South Platte River is also needed by the <br />Division 1 Engineer to better understand gains and losses of deliveries of water down the South <br />Platte River. Four reaches of the river where again/loss study is warranted are as follows: <br />• Jay Thomas Ditch (located upstream of the St. Vrain River) to the gage at Kersey <br />• Kersey gage to Weldona gage <br />• Weldona gage to Balzac gage <br />• Balzac gage to Julesburg gage (state line) <br />Within each reach, flows would be measured at the endpoints on the South Platte and at all direct <br />inflows to and diversions from the river. Two to four intermediate flows in the river will also be <br />measured for each reach depending on reach length. Overall, there are 15 tributaries which flow <br />to the South Platte River (three of which are presently gaged) and 56 diversions or outfalls <br />associated with diversions and reservoirs. Where gaged records are available, the point flow <br />monitoring program will utilize that data; otherwise, field measurements of flow will betaken. A <br />total of four measurement events will be conducted for the four reaches of the river. The <br />program will take place over two years, with gaging performed during the following distinct <br />periods: late fall (October-Nov) of year one, early spring (March-April) of year two, and late <br />summer of both years 1 and 2 (August). <br />p:data\gen\spdss~final report\chapter 3.doc 3-6 <br />October 31, 2001 <br />