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. . The following points summarize Ihe findings of the diversion struclure assessment and indicate key stream diversion problems and issues Ihat must be addressed in the RGHRP plan. The 6 major diversions on Ihe river (those with a decreed capacity of more than 300 cfs, including Rio Grande Canal, Prairie Ditch, Farmers Union Canal, Monte Visla Canal, Empire Canal and San Luis Valley Canal) comprise 80 percent of the total decreed diversions within the study reach. Of those, four diversions (Rio Grande Canal, Farmers Union Canal, Prairie Ditch and Monte Vista Canal), which represent 61 percent of the total decreed diversions within the study reach, are in good condition. . Channel conditions at diversions in the upper end of the system near South Fork are fairly stable. Some debris buildup is evident at the diversions. Sedimentation in diversions along the steeper portions of the channel upstream of Del Norte is a major problem. Few of the structures have wasteway channels to allow sluicing of sediments. Channel instability also becomes a problem in this area. Diversion density is fairly high in this area at an average of 0.8 diversions per mile. Therefore, diversion consolidation should be considered. Only one diversion (McIntosh Arroyo Ditch) is contained in the South Channel. Relocation of the diversion structure to allow other project objectives to be maximized in the South Channel should be considered. . major Diversions between the Del Norte split flow confluence and the Consolidated Slough (Reach C) are generally in good condition. The exception is McDonald Ditch, which utilizes the old Sevenmile Bridge structure as a diversion and was given a fair rating. The density of diversions within Reach C is the highest in the study reach at an average of 2 diversions per mile of stream length. However, because the river and diversions are in good condition, consolidation is not necessarily recommended. Channel instability is a major problem for diversions from the Consolidated Slough downstream through the Wests ide Diversion. All diversions were given fair to poor ratings. Channel avulsion, lack of channel capacity, sedimentation, and debris accumulation are all problems at these diversions. . The density of diversions between the Consolidaled Slough and Centennial Dilch is fairly high at 0.6 diversions per mile. Diversion consolidalion should be considered at several locations to maximize diversion efforts at fewer diversion locations. . 4 ES- The Westside Diversion Dam is in poor condilion, and is causing capacity problems within the Alamosa levees. The dam should be removed and the diversion consolidated or redesigned to significantly reduce or eliminate its impacts on the Alamosa levees. The New Ditch diversion on the Alamosa National Wildlife Refuge has inadequate capacity and obstructs river flows. . Overall Rating Good Fair Fair Good Fair Fai"r Fiijf F8ir Poor Poor Fair Good Good Poor Fair Fair Poor Good Fiijf Fiijf Good Good Fiijf Poor Poor Poor Poor Poor Fair Poor Poor Fair Fair Poor Fair Poor Good Fair Good Good Good Good Good Good Good Good Good Good . and no Diversions from the North Channel are all in fair to good condition, restoration efforts on the North Channel are required for diversion purposes. . Diversion Structure Capacity and Overall Ralln<< Location Sub Est. Capacity Dec. Capacity lr~le) R~h ~ ~ J.gll R no records no records 121.4 A2 40 38.76 i18.f A3 70 39.48 i17.5 A3 50 46.86 i16.ij' A3 15 10.67 i14.4 A3 40 67.23 i13.8 A3 15 12.35 112.4 A4 15 15.25 109.9 A4 2 1:05 108.2 AS 10 ----s:2 106.1 A5 5 4 104.7 ~ 1900 1648.5 104.7 A6 6 4.4 103.7 M 40 -W- 103.6 M T 1'2 103.3 M 18 ---sil 9B BB2 8 ------;r- 95.2 C1 25 18.8551 95.2 C1 8 ----;j 93.8 C1 20 14.4 93.4 C2 380 367.02 92.6 C3 380 340.77 92.6 C3 96 94.48 91.6 D1 4' 1:4 91.9 D1 9Q.7 D1 87.8 D2 87.2 D2 84.6 D4 83.2 D4 79.9 OS ?IT 156 76.1 D7 65.6 E3 57T E5 5Q.9 F2 49.5 F2 42.6 G2 103.3 BA1 103.3 BA 1 103.3 BA1 103.3 BA1 103.3 BA1 103.3 BA1 103.3 BA1 103.3 BA2 103.3 BA2 103.3 BA2 6.8 9.3 iT.2 505.92 34.94 500.98 82.4 89.7 103.3 1i2 35.8 66.4 30.43 1.34 4:8 42 ~ 3:B S- 3:B 1.95 ---1- 801.45 o o !Q 550 ~ 400 100 120 1iO 20 47 120 120 T 2- ..!L 24 ""5 10 T 4 2- 910 Diversion Name RIVIERE ESTATES AUG PLAN ANACONDA 0 MINOR D MEADOW GLEN 0 PFEIFFER D INDEPENDENT D 2 EHROWITZ D BAUER D ATKINS D PARK GREEN D DYER D RIO GRANDE CNL SCHUCH SCHMIDT MIDLAND D RIO GRANDE D 4 RIO GRANDE D 1 MCINTOSH ARROYO 0 SILVA 0 ATENCIO 02 MCDONALD 0 PRAIRIE 0 MONTE VISTA CNL RIO GRANDE PIEDRA VL Y 0 PACE 0 CONSOLIDATED SLOUGH BUTLER D FISH D NICHOL 0 EMPIRE CNL BILLINGS 0 SAN LUIS VALLEY CNL CENTENNIAL 0 EXCELSIOR D COSTILLA D INDEPENDENT 0 WESTSIDE 0 CHICAGO 0 NEW DITCH WEISS D BREY 0 RIO GRANDE 02 KANE CALLAN 0 ANNA RABER 0 OFFD RABER D HALL-VOSS D COCHRAN PIONEER 0 FARMERS UNION CNL . Table ES-3. !Q. 7022 511 752 742 787 681 614 528 965 782 ~ 812 833 747 815 810 737 846 518 736 798 753 811 781 l 556 636 775 623 546 829 566 627 587 680 903 575 773 901 552 814 699 513 777 801 966 582 631 ES-13