Laserfiche WebLink
<br />dense, composed of stiff brush and grasses which occasionally encroach <br />on the mai n channel area. A Manni ng roughness coeffi c i ent of .055 is <br />assigned to the main channel and .070 for the overbank areas. <br />Downstream of Ni agara, Mont rose Mroyo enter's Rotary Pal"k. <br />Between Niagara and a small pump diversion structure, the channel' sec- <br />tion is irregular, with some weed and qrass growth in the main channel. <br />The left overbank area is covered with relative'ly dense brush growth, <br />whil e the ri ght overbank is 1 ess overgl"own. The ass i gned roughness <br />coefficients for this reach were .045 for the main channel, ,,05:; for <br />the left overbank and .050 for the right overbank. <br />Downstream of the park irrigation pump diversion structure, to S. <br />12th Street, the channel is more regular. The right overbank area is <br />all well maintained, mowed grass. The left overbank is more overgrown, <br />with some stiff brush present. For this reach, a roughness coefficient <br />of .035 was used for the right overbank and main channel and .050 for <br />the left overbank. <br />From S. 12th Street to S. 4th Street, Montrose Arroyo is in an <br />urbani zed area and is crossed numerous ti mes. In thi s reach, the mai n <br />channel is smaller, more confined and better defined. Clumps of grass <br />a nd weeds grow a] ong the water li ne, wi ':h the overhank area re 1 at i ve 1 y , <br />clear except for occasional trees and grasses. Various structures (in <br />addit i on to the roads) cross over the st ream, incl ud i ng footbri dges and <br />pipes. A roughness coefficient of .040 has been utnized in this reach <br />for the main channel and .045 for the overbank areas. <br />The S. 12th Street crossing is an 8 foot wide x 3.3 foot high <br />RCBC, with wingwalls. At S. 9th Street, a 66 inch diameter CMP is pro- <br />vided, with full headwall and wingwalls. The stream crosses S. 8th <br />Street at Park Avenue in a 15.9 foot wide x 7.5 foot high SPPA. <br /> <br />9 <br />