Laserfiche WebLink
in flow does not translate to an proportional increase in water depth. The <br />maximum depth at 100 cfs is 2.2 feet, compared to 2.5 feet at 300 cfs, and 3.0 <br />feet at 600 cfs. The mean water depth at 100 cfs is 0.8 feet, compared to 1.1 <br />feet at 300 cfs, and 1.3 at 600 cfs. <br />Transect No. 4 (Appendix; Figure G.2.) <br />This transect was located at RM 2.8 and was the third widest transect, 446 <br />feet. At 300 cfs, the mean and maximum water depth was 0.5 and 1.1 feet, <br />respectively. Although there were two defined thalwegs across this transect, a <br />flow of 1,600 cfs would be required to maintain a mean water depth of 1 foot. <br />A maximum water depth of 1 foot was exceeded only once each at 300, 400, 500, and <br />600 cfs. If a mean 1-foot water depth is to be maintained, this is a critically <br />shallow cross section at 300 cfs. <br />Transect No. 5 (Appendix; Figure G.3.) <br />This transect was located at RM 2.8 where the river narrows and makes a 45° <br />left-hand bend. A maximum water depth of 2 feet is achieved at 600 cfs. At 300 <br />cfs, mean and maximum water depth was 1.0 and 1.6 feet, respectively. At 200 cfs <br />50% of the predicted water depths exceeded 1 foot. <br />Transect No. 8 (Appendix; Figure G.3.) <br />This transect was located at RM 2.75 and extended 269 feet. A 200 cfs flow <br />maintains a 1-foot mean and 2-foot maximum water depth, respectively. Forty- <br />three percent of predicted observations exceeded 1 foot at 200 cfs; 57% exceeded <br />1 foot at 300 cfs. <br />Transect No. 9 (Appendix; Figure G.4.) <br />This transect was located at RM 2.7 and extended 273 feet. This transect <br />is slightly downstream of FWS Transect No. 9. At 300 cfs, the mean and maximum <br />water depth was 0.5 and 1.2 feet, respectively. At 600 cfs, the mean and maximum <br />water depth increased by only 0.2 and 0.4 foot. A mean water depth of 1 foot was <br />maintained at 850 cfs. A 1,600 cfs flow would be required to maintain a 2-foot <br />mean water depth at this transect. At 300 cfs, only one of 15 (7%) predicted <br />observations exceeded 1 foot; at 400 cfs, only one of 21 (5%) ; at 500 cfs, only <br />two of 21 (10%). There was not a well - defined thalweg across this transect. If <br />at least a 1-foot water depth is to be maintained, this is also a critically <br />shallow cross section at 300 cfs. <br />Transect No. 12 (Appendix; Figure G.4.) <br />This transect was located at RM 2.1 and extended 329 feet. A mean water <br />depth of 1 foot is maintained at 400 cfs. However, at 300 cfs, approximately 38% <br />of the predicted observations exceeded 1 foot. Doubling the flow from 300 cfs <br />to 600 cfs only increases the maximum water depth from 2.6 to 3.2 feet. <br />Therefore, the increased available habitat is disproportional to an increase in <br />flow of this magnitude. <br />22