Master Drainage Plan Report
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CITYCITY OFOF GALVESTONGALVESTON MASTERMASTER DRAINAGEDRAINAGE PLANPLAN PreparedPrepared for:for: CITYCITY OFOF GALVESTONGALVESTON PreparedPrepared by:by: DANNENBAUMDANNENBAUM ENGINEERINGENGINEERING CORPORATIONCORPORATION (Prime)(Prime) ProjectProject Team:Team: BergBerg OliverOliver Associates,Associates, Inc.Inc. DodsonDodson && Associates,Associates, Inc.Inc. KathyKathy ThomasThomas BarrBarr TerraPointTerraPoint July,July, 20032003 CITY OF GALVESTON MASTER DRAINAGE PLAN Prepared for: CITY OF GALVESTON Prepared by : Prepared by: DANNENBAUM ENGINEERING CORPORATION (PRIME) In association with: Berg Oliver Associates, Inc. Dodson & Associates, Inc. Kathy Thomas Barr TerraPoint May, 2003 GALVESTON MASTER DRAINAGE PLAN TABLE OF CONTENTS EXECUTIVE SUMMARY ...........................................................................................i-viii 1. INTRODUCTION ...................................................................................................1 2. PROJECT TEAM ....................................................................................................1 3. PROJECT DATUMS AND BENCHMARKS ........................................................2 4. DATA COLLECTION/GIS MAPPING..................................................................3 5. DRAINAGE CRITERIA EVALUATION ..............................................................4 6. EXISTING STORM WATER FACILITY MAINTENANCE OPERATIONS......5 7. EXISTING CONDITIONS SYSTEM.....................................................................6 A. Storm Sewer Systems ........................................................................................7 B. Bridge Blocks...................................................................................................18 C. Open Channel Systems ....................................................................................19 1. Pelican Island............................................................................................19 a. Criteria and Methodology..............................................................20 b. Results ............................................................................................20 i. System “A” ........................................................................21 ii. System “B”.........................................................................21 iii. System “C”.........................................................................22 iv. System “D” ........................................................................22 v. Systems “F” and “G” .........................................................23 vi. Pelican Island Industrial Park (PIP) System ......................23 c. Construction Cost...........................................................................23 2. West End Problem Areas...........................................................................24 a. Bay Harbor.....................................................................................24 b. Terramar Beach..............................................................................25 c. Sea Isle...........................................................................................26 d. Habla Road.....................................................................................26 e. Bermuda Beach/ Pabst Street.........................................................26 f. Gulf Palms Drive ...........................................................................27 g. Palm/Pirates Beach ........................................................................27 8. PROPOSED CONDITIONS SYSTEM IMPROVEMENT METHODOLOGY ..27 -1- G:\1110\HHENG\3543-01\CD-REPORT\final-Report-rev5-09.doc TABLE OF CONTENTS (CONT’D) 9. PROPOSED STORM SEWER SYSTEM IMPROVEMENTS A. Storm Sewer Areas ..........................................................................................28 B. Bridge Blocks...................................................................................................39 C. Open Channel Systems (West Galveston – Non-Seawall Areas)....................40 10. CONSTRUCTION COST ESTIMATES .............................................................48 11. OPERATIONS AND MAINTENANCE ..............................................................48 12. CAPITAL IMPROVEMENT PROGRAM AND EQUITABLE STORM WATER RATE FEE DETERMINATION ............................................49 13. MASTER DRAINAGE PLAN SUMMARY AND CONCLUSIONS..................55 TABLES 1. Existing Storm Sewer Summary (Sheet 1 – 9) 2. Proposed Storm Sewer Summary (Sheet 1 - 7) 3. Pelican Island Summary – System “A” 4. Pelican Island Summary – System “B” 5. Pelican Island Summary – System “C” 6. Pelican Island Summary – System “D” 7. Pelican Island Summary – System “F&G” 8. Pelican Island Summary – System “PIP 9. Capital Improvement Plan Summary 10. Master Drainage Plan Cost Analysis 11. Master Drainage Plan Equitable Storm Water Fee Analysis EXHIBITS 1. Vicinity Map 2. Galveston Island Key Map 3. Galveston Drainage Block Maps (Under Separate Cover including Key Map) 3.1 Grid 1, 2, 23 3.2 Grid 3, 4, 24, 25 3.3 Grid 5, 6, 26, 27 3.4 Grid 7, 8, 28, 29 3.5 Grid 9, 10, 30, 31 -2- G:\1110\HHENG\3543-01\CD-REPORT\final-Report-rev5-09.doc TABLE OF CONTENTS (CONT’D) EXHIBITS (Cont’d) 3.6 Grid 11, 12, 32, 33 3.7 Grid 13, 14, 34, 35 3.8 Grid 15, 16, 36, 37 3.9 Grid 17, 18, 38, 39 3.10 Grid 19, 20, 40, 41 3.11 Grid 50, 51 3.12 Grid 52, 53, 59, 60 3.13 Grid 54, 55, 61, 62 3.14 Grid 56, 57, 63, 64 APPENDIX (Under Separate Cover) 1. Working Storm Sewer Maps • Existing Conditions Maps • Proposed Conditions Maps 2. West Galveston Calculations 3. Equitable Storm Water Fee Calculation Information/Cost Estimates 4. Resident Survey Result Tables 5. Pelican Island Data • Cost Estimate Table • Excavation/Quantity Estimates 6. Scope of Work 7. Public Meeting Information 8. Miscellaneous Information • LandData Survey and Storm Sewer Sediment Estimates • FM3005 Structure Inventory • Galveston Average Rainfall (30yr) • GCAD – Land Use Codes • Adopted Rules for the Management of the Beach Dune System – GLO • Municipal Drainage Utility Systems Act – Subchapter C: Municipal Drainage Utility Systems • Jamaica Beach Rainfall (August 2002) • Reference Tables – Rainfall and Tidal Data (From Harvey Scheffer & Associates in previous 1980 Master Plan) -3- G:\1110\HHENG\3543-01\CD-REPORT\final-Report-rev5-09.doc EXECUTIVE SUMMARY This report presents the findings of the City of Galveston Master Drainage Plan. The primary purpose of this report is to develop a plan for the City of Galveston to comply with the U.S. Environmental Protection Agency (EPA) mandate regarding the storm water quality or National Pollution Discharge Elimination System (NPDES), with help from Dodson and Associates (in separate reports). The secondary purpose of this Plan is to evaluate existing drainage conditions on Galveston Island and Pelican Island controlled by the City of Galveston (including Galveston County MUD #1, but not including Jamaica Beach a separate City), and to recommend improvements that can be phased in over a period of years. This Plan will include elements of NPDES (Dodson and Associates), storm sewer, surface drainage (Dannenbaum Engineering), environmental conditions (Berg Oliver Associates), and public involvement (Kathy Thomas Barr Communications). This plan is not intended to address flooding issues associated with tropical weather events such as hurricanes, tropical storms and depressions. The high tides and storm surges that occur during these events are beyond the scope of this study. Galveston Island is a barrier island along the Texas Gulf Coast, and the City of Galveston is the largest island community in the United States established on a barrier island. The Gulf of Mexico is the southern boundary, and Galveston Bay forms the northern boundary of the island. This geographic location results in a number of natural events and conditions that impact drainage on the island. These events include periodic tropical storms, or Hurricanes that originate in the Gulf of Mexico and create intense rainfall and are also accompanied by high tides that cause severe flooding of the lower elevations on the island. After the 1900 Hurricane the eastern portions of the island were raised behind a seawall completed in various stages from 1904 to 1961. Areas west of the seawall retain the natural barrier island characteristics. In addition to storm water run-off another contributor to the drainage system on Galveston Island is the sand itself. Galveston sand is very fine and easily gets airborne due to the prevailing onshore breeze. This sand is deposited over the areas directly adjacent to the beach side of the island and eventually drains into and gets deposited into the storm sewer system. The sand in addition to other sediments draining into the storm sewer system creates an on-going maintenance concern. This study includes a comprehensive look at the current drainage conditions on Galveston Island. The primary objectives were to: a) obtain good topographical information of the island to determine existing flow patterns; b) collect information on the existing storm sewer and culvert drainage systems and evaluate their performance; c) evaluate the current drainage criteria; d) determine the minimal improvements necessary to bring the current drainage system into line with the existing drainage criteria; e) determine construction cost for a CIP program; and f) determine an equitable storm water fee funding program for the City that could