Field Report for the South Platte River in Littleton South Platte Park

Home Browse Search

Boulder Cluster #1 (September 10, 1998) Instream cover for juvenile is provided on transects 1, 2 and 3 at 24 cfs by the boulder cluster #I grouping. Three cross - sections were placed adjacent to and across some of the boulders in boulder cluster #1 structure to determine water depths at the observed flow of 24 cfs (Figure 9). Channel depths at 24 cfs are less than those providing adult cover at any of these cross sections that were measured. Deepest water depths are approximately 1.2 feet deep and a depth of approximately 1.5 to 2 feet is needed to provide adult cover for trout during low flows. As shown by Figures 10 and 11, there is habitat provided for juvenile trout at flows slightly below 30 cfs, however, the adult habitat is limited by depth at these flows and at boulder cluster #1. As seen in the field report in the next section on visual observations and measurements taken at the remaining boulder clusters, there is trout habitat provided for adults based on depths measured at approximately 28 cfs at the remaining structures. Field Report for the South Platte River in Littleton South Platte Park Review of boat chutes, boulder clusters and deflectors South Platte River on September 18, 1998 was approximately 28 cfs. Flow information was provided by the Water Talk Station for the release of Chatfield Reservoir. The inspection started at boat chute no. 2. Boat chute no. 2 is on river right, looking downstream. A series of boulder clusters downstream of boat chute no. 2. The boulder clusters are nearly off channel and at the flow observed and lower flow measured on September 10, 1998, that boulder cluster is out of the water and ineffective at those flow ranges. Higher flow ranges may inundate the boulders but position is not good for providing habitat for that particular boulder cluster. Boat chute no. 3 is a series of boulders with guide rocks that show the opening to the boat chute. The flow is constricted to a mid- channel flow at the September 18` observation date. Water is greater than 2 feet deep downstream. Relatively large pool downstream of the chute which provides habitat and can provide habitat at even lower flows. The constriction has caused scouring during high flow and deposition of that material downstream of the boat chute. This downstream deposition controls water surface elevation up to the boat chute and provides deeper water habitat during low flow conditions. Boulder cluster no. 8, as noted on the maps, was proposed. It has not been installed and was not observed. Boulder cluster no. 3 provides good instream habitat with water depths greater than 2.5 feet near the boulders. It provides a low velocity in the stream adjacent to and behind the boulders to provide velocity shelter and instream cover for fish. Placement of the boulders is either at or Habitat Control Structure Investigations South Platte River in South Platte Park Downstream Of C -470 Page 3 Miller Ecological Consultants, Inc. November 6, 1998 A