RGDSS_Task6-1_HistoricMonthlyModel_Drainage

Home Browse Search

SOUCRECO South Crestone Creek, near Crestone, CO 5.92 NA SPACRECO Spanish Creek, near Crestone, CO 4.10 NA WILCRECO Willow Creek, near Crestone, CO 10.16 NA Ungaged Locations The calculation of baseflows is also necessary for modeling. These calculations prorate the gains between upstream and downstream gages and require the incremental basin area between the ungaged location and any upstream gages or upstream baseflow locations. Determination of drainage areas for these locations followed the same procedures used for determining areas at gage stations. Hardcopy topographic maps were first used to delineate drainage area boundaries, followed by digitizing these boundaries using MapInfo. Areas were then calculated using MapInfo SQL queries. The incremental drainage areas for ungaged locations are shown in Table 2. Note that many of these incremental areas are actually total tributary basin areas since gage records upstream of these ungaged baseflow points were either nonexistent or insufficient. (Additional discussion of the concept of drainage areas, FLOW(gage) points and other baseflow nodes can be found in the CDSS User's Manual - DMI Utilities - makenet.) A map displaying the gaged and ungaged drainage areas is included as Attachment 1. Table 2. Drainage Areas at Ungaged Locations Basin Description Rio Grande R. below Clear Cr. (incr) Rio Grande R. below South Fork (incr) Embargo Creek Pinos Creek Middle Creek San Francisco Creek Trout Creek Rio Grande R., below Pinos Creek Alamosa River La Jara Creek Upper La Jara Creek Hot Creek Fox Creek Massey Creek Mill /Big Horn Creek Trail Creek Rito Seco San Francisco Creek Torcido Creek Area mi2~ 164.00 89.25 68.52 89.21 9.64 27.68 37.58 1,465.47 189.44 322.24 36.09 62.52 24.27 4.74 13.15 2.44 33.65 29.68 7.32 C:\cdss\Task6-l.doc Drainage Areas and Proration Factors November 4, 1999 -Page 4 of 11