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e e e The northern boundary is the Gibraltar Ditch. The eastern boundary is the proposed diversion in the Yampa River near the old town site of Mount Harris. The western boundary is where the Shelton Ditch return flows enters the Yampa River one mile west of Hayden. The watershed is privately owned. There are thirty-four operating units in the project area. The average number of irrigate~ acres per unit is 143. The watershed currently has five different points of diversion and irrigation ditches to irrigate 4854 acres. Combined the five headgates have water rights to divert 150 cfs. Maps showing the area and the ditches are included as exhibit "A". , ./ ;I ',,,/1 1/..--/,' , /','"') '~,'" ",', , ""'7'/""': C __'5'r'C'-(.~_ ~L--C;Z(J' /.. ~ G: /-.- 'i...-'/.--<-t ". 10.- 4. NEED FOR THE PROJECT ,.-.- The yearly construction of these temporary diversion dams is an environmental disaster. They impede both fish and vessel passage. They wash out every year during the spring run-off sending sediment down stream. Furthermore, a portion of the rocky underpinnings of these dams usually remains. These partially submerged structures force the river during run-off to widen its channel. Excessive erosion is the result. Enclosed as exhibit "B" are photographs of a number of these structures before and after the run-off. We call attention in particular to the photos taken after the run~off of the Cary & Shelton Ditch Diversion structures. Notice how the river has widened its channel. In the case of the Cary Ditch project, financed largely by the District, by installing a permanent diversion structure upstream two temporary 'diversion dams on the river were eliminated. The time will very soon come when material from the river substrate to build these structures will no longer be there. What the ranchers will do then is hard to predict. In the case of the Smith Ditch Project, which CWCB helped finance, it became impossible to build a temporary diversion dam in 1995. No irrigation water was diverted for three year and productive irrigated ranch land lay fallow. The District installed a permanent dam structure with an air operated adjustable crest, which now permits late summer low river diversions. As a further indication of the need for this project, we mention that the District has spent over $350,000 on three such projects to correct the problem. s. AL TERNATIVES EVALUATED The Natural Resources Conservation Service (NRCS) authorized a preliminary report on the project and came up with alternatives, summarized as follows: Alternative I-No Actian The No Action alternative reflects changes that are expected to occur without project action. These changes include: river entrenchment, streambank erosion, periodic increased river sediment due to diversion construction activities, increased embeddedness of the river, obstruction of fish and vessel passage, and yearly washout of the temporary structures. The yearly construction costs of $1500 to $2000 per structure will continue with the prospect that substrate material in the near future will not be available. Again, we refer to exhibit "B" which illustrates examples of these temporary dams in place and washed out. 2