CROSSSECTION1(2000)-Layout1.pdfLayout1CROSSSECTION2(2000)-Layout1.pdfLayout1CROSSSECTION3(2000)-Layout1.pdfLayout1CROSSSECTION4(2000)-Layout1.pdfLayout1CROSSSECTION5(2000)-Layout1.pdfLayout1Greencastle Water Treatment PlantGreencastle, IndianaFlood Protection and Security PlanFinal ReportApril 2004United Geotech LTD 5500 Wabash Avenue Terre Haute, Indiana 47803 Serving the community for 25 years April 29, 2004 Mr. Glen Morrow, P.E. City Engineer City of Greencastle One North Locust Street, PO Box 607 Greencastle, IN 46135 Dear Mr. Morrow: United Geotech LTD would like to present you with the final report for the Greencastle Water Treatment Plant Project. The report outlines United Geotech’s design of the project. The body of the report includes the project scope and approach, design recommendations, and cost estimates. All of the calculations, maps, and final drawings are included in the appendices. The AutoCAD drawing files will be emailed for your use. Please feel free to contact us if you have any questions concerning the final report. It has been a pleasure working with you, and we hope that United Geotech will have the opportunity to do so again. Very truly yours, Sarah Bireley Project ManagerExecutive Summary The City of Greencastle is located in west central Indiana and has a population of approximately 10,000. The water treatment plant for the city is located along Big Walnut Creek. Glen Morrow, the city engineer for Greencastle, has three concerns for the plant: potential flooding of the plant, possible bank failure of a steep slope on the north side of the plant, and security of the plant in light of 9/11 terrorism. This report addresses all three concerns. Prior to proposing solutions for potential flooding, the 100-year flood elevation needed to be determined. Currently, only approximate flood elevations are available. Using the U.S. Geological Survey’s hydrologic regression equations and river modeling software, the 100-year flood level was determined to be approximately one and one-half feet above the finished floor level of the treatment plant. This provided sufficient rationale for flood protection, and a levee was determined to be the best option based on criteria supplied by the client. The proposed levee will be approximately 940 feet in length and will encircle the water treatment in a horseshoe shape starting east of the filter facility, running north, and continuing through to the east side of the lagoon. Each side of the levee will have a 1:2.5 side slope allowing for easy maintenance. The structure will be trapezoidal in shape, with a maximum base width of 68 feet and a top width of 3 feet along the entire length. The maximum height of the levee is 13 feet. The interior of the levee will be composed homogeneously of a clayey sand fill which is prevalent in the area. Our client wishes to expand the on-site lagoon, and the soil excavated form this location will be used to supplement some of the soil needs. The final cost of the levee will be approximately $71,500. The steep bank extending from 30 feet north of the plant down to Big Walnut Creek was analyzed for stability due to possible failure caused by the weight of the proposed levee. Using the stratigraphy found from the results of the soil testing, United Geotech was able to use a slope stability computer program to analyze the embankment under present and future conditions. The final analysis shows that the factor of safety for the slope with the added weight of the levee is two, thus, no slope stabilization will be needed. A 6-foot high fence with barbwire is proposed as an effective form of security. The total length of the fence will be approximately 1600 feet, and two gates will be needed in order to provide access for vehicles entering and exiting the site. The fence is to encompass the treatment facility, generator, water tower, aeration/detention structure, control pit, and garage. It will also tie into the existing lagoon fence. The final cost of the fence is approximately $24,000.Table of Contents 1.0 Introduction………………………………………………………………………………………... 1 2.0 Design Requirements…………………………………………………………………………….. 2 3.0 Project Approach…………………………………………………………………………………. 3 4.0 Engineering Analysis and Design………………………………...…………………………….. 3 4.1 Site Assessment…………………………………………………………………………... 3 4.2 Hydrology of Big Walnut Creek..………………………………………………………… 4 4.3 Hydraulics of Big Walnut Creek….………………………………………………………. 5 4.4 Codes and Regulations…………………………………………………………………… 5 4.5 Flood Protection Options…………………………………………………………………. 6 4.6 Soil Investigation…………………………………………………………………………... 7 4.7 Slope Stability……………………………………………………………………………… 8 4.8 Levee Design………………………………………………………………………………. 9 4.9 Seepage Analysis…………………………………………………………………………. 10 4.10 Post-Levee Hydraulics…………………………………………………………………... 11 4.11 Security Options…………………………………………………………………………. 12 4.12 Cost Estimation…………………………………………………………………………... 13 5.0 Conclusions and Recommendations...…………………………………………………………. 14 6.0 References………………………………………………………………………………………… 15 List of Appendices Appendix A - Site Assessment Appendix B - Hydrology of Big Walnut Creek Appendix C - Hydraulics of Big Walnut Creek Appendix D - Relevant Codes and Regulations Appendix E - Flood Protection Options Appendix F - Soil