Laserfiche WebLink
<br />Surveys were done in these clusters on September 10 and 11 at flow of 133 and 122 cfs, <br />respectively. At these flows bed profiles were surveyed at three shallow riffles that had maximum <br />depths of 1.0ft or less. The most downstream riffle was a cross section 2 in the sequence. The two <br />other riffle profiles were across gravel/cobble bars that were not perpendicular in the channel. <br />Since bed profiles had to measure the shallowest contour of these riffles, these profiles were <br />diagonal to the banks and therefore these sites would not model well at higher flows. <br /> <br />The deepest measurement at cross section 2, at 133 cfs was 0.64 ft. At this flow the WSL was <br />89.22. To achieve a depth of 1.0 feet at this cross section, WSL must rise 0.36 ft, or have an <br />elevation of 89.58, which is produce by a flow of 336 cfs. (Appendix 2, Table 6). <br /> <br />Cross section 7 was on a control and cross section 8 was located just upstream, at the lower end <br />of a run. A bed profile was done between cross section 7 and 8 on a shallow diagonal submerged <br />bar. At 122 cfs, the deepest reading was 1.0 ft. <br /> <br />Depth readings were made at the shallow riffle at the upper end of Cluster 63.5. This profile <br />was not surveyed because of land owner denial to access the left bailie Therefore, the uppermost <br />cross section (9), was across a scour pool, not the shallowest part of the riffle. The riffle above <br />cross section 9 was complex in that flow was split by a bar in midchannel and had perpendicular <br />flow on the left channel, but on the right channel flow was lateral across a very shallow cobble <br />riffle. Depth measurements were taken along the shallowest profile with the rod. The deepest point <br />was 0.6 ft. at the flow of 122 cfs (Table 6). <br /> <br />Cluster 7 (rm 73.3) <br /> <br />This cluster was surveyed at a flow of 288 cfs. A bed profile was taken at the shallowest part of <br />the riffle downstream of the control, cross section 1. The deepest reading was 1.27 feet at a WSL of <br />90.99. The flow that would produce a WSL of 90.72 was modeled to be 160 cfs (Appendix 2, Table <br />7). <br /> <br />Cross section 5 was across the shallowest part of the upstream riffle. The deepest measurement <br />was 1.42 ft at 288 cfs. A depth of 1.0 ft would be produced at a flow of 85 cfs (Appendix 2, Table <br />7). <br /> <br />Cluster 11 (rm 78.8) <br /> <br />This cluster was surveyed at a measured flow of 135 cfs. A bed profile was not taken at the <br />shallowest part ofthe riffle downstream of the control. The maximum depth on the control cross <br />section, which was noticeably deeper, was 0.91 ft. A flow of 163 cfs would be required to increase <br />the maximum depth to 1.0 ft on cross section 1. <br /> <br />The shallowest part of the upstream riffle had a maximum depth of 0.8 ft at the time the cluster <br />was surveyed. A flow of 230 cfs would be needed to produce a maximum depth of at least one foot <br /> <br />43 <br />