PAJARO RIVER, CALIF. (b) Pajaro Valley alternate plan B-Continued. (2) Federal annual charges: (a) Interest at 3 percent on $60,000. Net Federal annual charge for plan B. Net additional cost of maintain- 100 Net non-Federal annual charge for plan B.. Total annual charge for plan B.. (c) Existing levee project in Watsonville and vicinity: $1,800 530 1, 200 Net Federal Work Projects Administration annual (a) Interest at 4 percent on $181,210.--- (c) Estimated cost of maintenance and opera- 9, 640 1, 580 1, 300 1, 200 (d) Carnadero Creek levee project near Gilroy: (1) Federal first cost or net investment for new work $134, 790 4, 040 7, 245 1, 185 1, 200 Net non-Federal annual charge for existing Watson- $95, 810 181, 210 Total annual charge for existing Watsonville levee. $59, 000 (d) Carnadero Creek levee project near Gilroy-Continued. (a) Interest at 3 percent on $59,000.. (b) Amortization in 50 years at 3 percent $1,770 520 Net Federal annual charge for Carnadero Creek (3) Non-Federal first cost for easements and flowage (e) Existing levee project on Carnadero Creek near Gilroy: $6,000 240 Net non-Federal annual charge for Carna- (3) Non-Federal investment by local sponsors. Total added annual charge for Carnadero (a) Interest at 4 percent on $12,070.... ation.... 155 40 155 0 $21, 870 600 Net Federal Work Projects Administration annual $12, 070 480 290 655 155 Net non-Federal annual charge for existing Carna- Total annual charge for existing Carnadero Creek $2.00 1,855 BENEFITS FROM IMPROVEMENT 76. General. The considerations leading to the selection of the most practicable plans of improvement are discussed in paragraph Investigations have demonstrated that it is economically feasible t reduce flood damages in certain reaches of the Pajaro River and Carnadero Creek by means of the channel improvement described in paragraphs 67 to 70. works 2.130 ows up 2.570 1 $26,40 $15.90 atson ause a re, the 87100. 80. A enefits nds do ales and 82. The toposed stimated scussed Not print PAJARO RIVER, CALIF. 77. Protection provided. The proposed levee projects provide proection from all flows up to the 1-percent-chance flood for those reas which include urban developments and up to the 2-percentchance flood for those areas which contain little or no urban developSome measure of protection would be provided for floods of greater magnitude by the allowance for levee freeboard. However, the economic analysis of each proposed project, no reduction of damages is claimed for flows in excess of the flood magnitude for which that project is designed. nent. 78. Benefits from existing levees in Pajaro Valley. The present evees reduce the average annual damages in urban Watsonville by $18,100. In urban Pajaro and Watsonville Junction, and in agriultural lands above to mile 8.6, existing levees reduce the average nnual damages by $10,500. The total of the average annual benefits secured by these existing levees therefore amounts to $28,600. 79. Additional benefits afforded by plan B.-Protection of urban Watsonville from all flows up to the 1-percent-chance flood would cause a total reduction of $19,300 in the average annual damages. This is an added benefit of $1,200 over those provided by the present evee system. In urban Pajaro and Watsonville Junction, and in agricultural lands as far upstream as mile 8.6, protection from all lows up to the 1-percent-chance flood would cause a total reduction of $26,400 in the average annual damages. This is an added benefit of $15,900 over those provided by the present levee system. Therefore, the average annual benefits added by plan B would amount to $17,100. 80. Additional benefits afforded by plan A.-Under plan A, the benefits of plan B would be secured and, in addition, the agricultural lands downstream from the existing levees to the river mouth on both sides and upstream therefrom to river mile 10.6 on the left bank and to river mile 11.8 on the right bank would benefit by further reduction in average annual flood damages amounting to $23,500. This is the average annual benefit added by plan A to that which would accrue under plan B. The total average annual benefit added by plan A would therefore amount to $40,600. 81. Benefits afforded by the Carnadero Creek levee project. The present levees provide average annual benefits in the vicinity of Gilroy amounting to $900. The proposed plan would afford protection of urban Gilroy and agricultural lands on the left bank of Carnadero Creek from mile 7.7 to mile 9.25 from all flows up to the 1-percentchance flood, providing added average annual benefits amounting to $3,100. 82. The evaluated average annual benefits expected to accrue from the proposed projects are all in the form of damages prevented and are estimated by the method explained in paragraph 35 and, more fully, discussed in appendixes IV and VIII. They are summarized in tables XVII and XVIII. 1 Not printed. TABLE XVII.-Summary of evaluated average annual damages prevented in the f Pajaro Valley [be tv (b) Protection with existing project. (c) Added protection under proposed plan.. 15, 300 19, 300 00 0 15, 300 19,300 Damage area and degree of protection provided Urban Pajaro and Watsonville Junction and agricultural lands to above mile 8.6 $8,300 10, 500 12,500 3,400 15,900 20,800 5,600 26, 400 0 Urban Gilroy and agricultural lands on left bank intermediate between (a) Combined protection for all flows up to magnitude of the 1-percent- 0 20,800 5,600 26, 400 Agricultural lands below existing levees to river mouth on both sides and above 0 Direct 0 0 0 $3,600 800 2,800 0 $20,500 3,000 23,500 TABLE XVIII.-Carnadero Creek levee, summary of evaluated average damages prevented antal $400 $ 40 2.300 20,500 緊 23,500 6130 Average annual damar Indirect Titl or DI asth 201 eadily pro At Gil JUSTIFICATION OF PROJECTS AND ALLOCATION OF COSTS 83. Ratios of evaluated benefits to costs. The annual benefits costs which, it is estimated, would be added by construction of the proposed projects to those which now accrue from the existing works are set forth in table XIX, complete with resulting economic rats. By comparison it is seen that project B has a higher economic th than project A. However, comparison of the added benefits and the added costs (table XIX, item 1c) of project A over project B results the er for enefit Pajaro R PAJARO RIVER, CALIF. in a favorable 1.10 to 1.0 economic ratio for the difference in cost of the two projects, indicating that the additional expenditure necessary for project A is well justified. In view of the ample economic justification and the larger social benefit to the whole community from the larger project, and the fact that local interests will more readily support it, project A is selected as the most practicable plan of mprovement in Pajaro Valley, with an economic ratio of 1.16 to 1.0. At Gilroy, the additions to the Carnadero Creek levee are justified by the prospective benefits with an economic ratio of 1.20 to 1. Matter for further comparisons is presented in table XX wherein the added benefits and project costs are combined with the benefits and costs of existing works and the economic ratios reflect the over-all conditions for the proposed projects. TABLE XIX.-Ratios of the benefits to costs added to those for existing works by the proposed projects Project (a) Existing levees... Project Total.. TABLE XX.-Ratios of total evaluated benefits to costs for the proposed projects in conjunction with existing works Project Pajaro Valley levee project, plan A. Added Added $35,000 21,350 Total an- $14,870 49,870 2, 180 4,750 $497, 700 556, 700 $40, 600 17, 100 23,500 Total annual benefit $28, 600 900 4,000 Economic ratio 1.16. 1.25 1. 10 1.20 84. Allocation of first cost of most practicable projects. It is considered to be an established policy to allocate the cost of levee construction and the cost of required modifications in railroad bridges, including all work items made necessary by such construction, entirely to the United States, and to allocate the cost of easements for construction and maintenance, necessary relocation of improvements to land, and modifications in highway and street bridges and approaches, to local interests. On this basis, the estimated Federal and nonFederal first costs are set forth in table XXI. All maintenance charges are allocated to local interests. TABLE XXI.-Project first cost allocations $243, 300 6,000 249, 300 Economic ratios for total project 1.92 to 1.0. 1.60 to 1.0. 1.39 to 1.0. 0.41 to 1.0. 0.84 to 1.0. Federal first Non-Federal Total project $741,000 65,000 806,000 |