2009 - Illinois DNR - State of Illinois

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Lowering the normal pool elevation of Belleau Lake 4 feet by installing a gravity outletpipe just above the flowline elevation of Farmers Creek (Alternative S8), provides aneconomically feasible, and relatively inexpensive, means to provide flood damagereduction benefits ($16,628) along Lower Farmers Creek. However, the additionalexpense ($700,000) to expand Belleau Lake to the north is not warranted for the minimal($5023) flood damage reduction benefits that would be derived.CHANNEL CONVEYANCERestrictive culverts under Dee Road and a private driveway off of Rancho Lane greatlycontribute to flood damages along Prairie Creek. Improving the channel conveyance ateither or both of these locations would provide flood damage reduction benefits alongPrairie Creek. However, these improvements would also increase discharges on LowerPrairie Creek and Farmers Creek resulting in increased downstream flood elevations andflood damages over baseline conditions in those reaches. The study shows that each ofthe channel conveyance alternatives investigated would increase discharges on LowerPrairie Creek and Farmers Creek resulting in increased downstream flood elevations andflood damages over baseline conditions in those reaches. Accordingly, each of the standalone channel conveyance alternatives were considered unacceptable unless combinedwith additional flood storage improvements to offset the increased discharge impacts.Unfortunately, the study also shows that combining improved channel conveyance andadditional flood storage capacity provides flood damage reduction benefits to many ofthe same floodprone structures in the watershed thereby increasing project costs withoutsubstantially increasing flood damage reduction benefits (see Table 8 - CombinationImprovements).Table 33 provides a break down of estimated project and construction costs as well aspotential state and local implementation partnering costs based on the capitalized valueof the flood damage reduction benefits for each alternative in the study. This tableshows what portion of each alternative’s construction costs could be covered by thecapitalized value of the flood damage reduction benefits potentially produced by thatalternative. The capitalized value of the flood damage reduction benefits exceed thecosts to construct addition flood water storage capacity at the Dude Ranch (alternativeS1 and S12), Good Avenue Pond (Alterative S2), Lutheran General Hospital Pond(Alternative S3), and at Belleau Lake (Alternative S8).Table 33 also shows that some of the combined storage alternatives (Alternatives S9 andS11) and some of the combined storage and conveyance alternatives (Alternatives D3,D4 and D7), have capitalized flood damage reduction benefits that exceed 75% of the135
costs to construct these improvements. These alternatives may warrant furtherconsideration for jointly (Federal, state and local) funded construction. Alternativeswhere the capitalized value of the flood damage reduction benefits do not exceed 75% ofthe costs to construct the improvements may not warrant further consideration for jointlyfunded construction.To reduce the risk of flood damages in the watershed, Cook County MWRDGC and/orthe city of Des Plaines and/or the city of Park Ridge should:1. Work with the Illinois Department of Natural Resources, Office of WaterResources to further plan and implement additional flood storage capacitymodifications at Belleau Lake, Dude Ranch, Good Avenue Pond, LutheranGeneral Hospital pond, or a combinations of these sites where the capitalizedvalue of the flood damage reduction benefits exceed 75% the costs to constructaddition flood water storage capacity. Such work would be completed inaccordance with the terms of a local project sponsorship agreement outlined in thisreport;2. Work with the Illinois Department of Natural Resources, Office of WaterResources to further plan and implement combined storage and conveyancealternatives at Rancho Lane and/or Dee Road where the capitalized value of theflood damage reduction benefits exceed 75% the costs to construct theimprovements. Such work would be completed in accordance with the terms of alocal project sponsorship agreement outlined in this report;3. Install a flap gate on the downstream (east) end of the 15-inch culvert underParkview Lane near Busse Highway, and consider raising portions of ParkviewLane and Busse Highway to provide additional freeboard protection againstFarmers Creek flooding;4. Encourage the purchase of National Flood Insurance and enforce local floodplainordinances in accordance with National Flood Insurance Program guidelines toprevent future floodway encroachments (including temporary storage ofequipment and materials), diminish future flood damage potential, and minimizefloodplain development in the watershed;136
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Alternative C5 - Pipe From Lutheran
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27. Alternative D6 - Combine Altern
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As shown in Exhibit 1, the study ar
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construct addition flood water stor
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PURPOSE AND AUTHORITYThis report hi
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infrastructure and commercial devel
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Central Road20120220620420710110410
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TABLE 3: CRITICAL DURATION DETERMIN
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Prairie Creek is modeled as a singl
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TABLE 5 CONTINUED: CALIBRATION DATA
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average annual damages under existi
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EXHIBIT 5: SAMPLE FLOOD DAMAGE COMP
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DAMAGE RESULTS TABLE 8PLAN DESCRIPT
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FLOOD DAMAGE REDUCTION ALTERNATIVES
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STORAGE IMPROVEMENTSALTERNATIVE S1
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Table 9: Alternative S1 - Dude Ranc
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Exhibit 7: Alternative S2 - Good Av
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ALTERNATIVE S3 - LUTHERAN GENERAL H
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Table 11: Alternative S3 - Lutheran
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Exhibit 9: Alternative S4 - Luthera
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ALTERNATIVE S5 - HIGH SCHOOL RESERV
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Table 13: Alternative S5 - High Sch
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Exhibit 11: Alternative S6 - Bellea
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ALTERNATIVE S7 - LAKE MARY ANNE PUM
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Table 15: Alternative S7 - Lake Mar
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Exhibit 13: Alternative S8 - Bellea
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ALTERNATIVE S9 -COMBINED STORAGE AT
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normal flows to bypass the lake in
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Table 17: Alternative S9 - Combined
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An additional 50 acre-feet flood st
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Table 18: Alternative S10 - Combine
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the flood storage at the site by ap
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Table 19: Alternative S11 - Combine
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Exhibit 17: Alternative S12 - Dude
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CONVEYANCE IMPROVEMENTSALTERNATIVE
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ALTERNATIVE C3 - DEMPSTER STORM SEW
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ALTERNATIVE C5 - PIPE FROM LUTHERAN
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ALTERNATIVE C7 - REPLACE RANCHO LAN
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OTHER IMPROVEMENTSALTERNATIVE L1- P
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COMBINATION IMPROVEMENTSALTERNATIVE
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damages for 59 structures currently
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Table 22 Continued: Alternative D1F
Page 92 and 93: Hospital property, north of Dempste
Page 94 and 95: Table 23: Alternative D2 - Combine
Page 96 and 97: sewer system would be restricted to
Page 100 and 101: sewer system would be restricted to
Page 104 and 105: Exhibit 31: Alternative D5 - Combin
Page 106 and 107: ALTERNATIVE D6 - COMBINE STORAGE AL
Page 114 and 115: Exhibit 34: Alternative D8 - Combin
Page 116 and 117: ALTERNATIVE D9 - COMBINE STORAGE AL
Page 118 and 119: Existing flood damages along Lower
Page 120 and 121: Table 30 Continued: Alternative D9F
Page 126 and 127: ALTERNATIVE D11 - COMBINE STORAGE A
Page 128 and 129: Exhibit 37: Alternative D11 - Combi
Page 130 and 131: Table 32 Continued: Alternative D11
Page 133: ALTERNATIVE D13: PRAIRIE CREEK CULV
Page 136 and 137: community can realize additional re
Page 138 and 139: concrete block or brick veneer over
Page 141: CONCLUSIONSFarmers and Prairie Cree
Page 145 and 146: S1S2S3S7S8S12S11S9D7TABLE 33 Farmer
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2009 - Illinois DNR - State of Illinois

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