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HomeMy WebLinkAboutWastewater ReportWASTEWATER DESIGN REPORT Gateway Phase 3 Richard Carter Survey, A -8 College Station, Brazos County, Texas October, 2007 O F r •% * 1 ................::: ALFRED A. PAINE .. .................. 97221 a a�26 /Z�'T PREPARED BY: Kling Engineering & Surveying 4101 Texas Ave., Suite A Bryan, Texas 77802 (979) 846 -6212 WASTEWATER DESIGN REPORT Gateway Phase 3 Richard Carter Survey, A -8 College Station, Brazos County, Texas October, 2007 PURPOSE: The purpose of this report is to analyze the existing and proposed sanitary sewer collection lines' capability of handling the increased demand from Gateway Phase 3. The subdivision is approximately 6.2 acres however, due to portions of the tract being located within a FEMA floodway, only 4.0 acres of proposed commercial use land are available for development.. The proposed public sanitary sewer system is composed of approximately 435 LF of a 8" PVC sanitary sewer line. The proposed system will connect to an existing 12" PVC sanitary sewer line running adjacent to the project site. The impact of the sewer demand to the existing 12" public sanitary line due to development of Gateway Phase 3 commercial subdivision is included in this report. As part of this analysis, contributing areas upstream of the proposed connection point were analyzed to calculate the existing flows through the downstream system. Previous Wastewater Design Reports were used to obtain existing demands. This report is being conducted in compliance with the B %CS unified Design Guidelines for Sanitary Sewer. WASTEWATER DESIGN REPORT Gateway Phase 3 DESIGN PARAMETERS: EXISTING CONDITIONS: Currently, a 12" PVC sanitary sewer line runs on the west side of the project site, flowing from south to north. The contributing area is approximately 95 acres, including Gateway Phase 3. Information for the contributing flows was obtained from prior reports in the area. Within the contributing area, the known flows from previous reports include University Town Center, The Veranda, Cedarcreek Condominiums, Homewood Suites, Hawthorne Suites, Post Oak Forest, McAlister's Deli, M.D.W. Centre, Grand Oaks, Amerisuites, Mariott, Microage, Holiday Inn, residential lots in University Park and the Gateway Phase 4 Condominiums (see Appendix 2 - "Design Parameters "). The previous reports referenced: Sanitary Sewer Impact Analysis "Bert Wheeler, Inc. 8.741 & 4.242 Acre Tracts ", Kling Engineering & Surveying, August, 1997. Wastewater Design Report "University Town Center, Phasel ", Kling Engineering & Surveying, December, 2004. Wastewater Design Report "University Town Center, Phase 2 & 3 ", Kling Engineering & Surveying, May, 2005. Water & Sanitary Sewer Report "M.D.W. Centre (Fully Developed) Commercial Development, 1200 University Drive East, College Station, Texas ", Rabon Metcalf Engineering, January 23, 2006, Rev. April 5, 2006. Wastewater Design Report "Gateway Phase 4 ", Kling Engineering & Surveying, November, 2006. WASTEWATER DESIGN REPORT Gateway Phase 3 The total existing flows can be seen in the following table. Table 1 Usage Avg. Daily (gpm) Peak Hourly (gpm) Report Reference Post Oak Forest 4.99 19.97 McAlister's Deli 0.78 3.12 ** University Town Center, Ph. 1 3.40 13.60 ** Homewood Suites 5.76 23.06 * ** Veranda Condominiums 7.50 30.00 * ** Cedarcreek Condominiums 13.96 55.83 * ** Hawthorne Suites (Quality Suites) 16.88 67.50 * ** Grand Oaks, Townhouses, and Duplexes 13.33 53.33 * ** University Town Center, Ph. 2 & 3 30.21 120.84 * ** M.D.W. Centre 28.00 112.00 * * ** Commercial 0.63 2.50 Commercial - Office 1.77 7.08 * * * ** Commercial - Hotel 12.57 50.28 * * * ** Commercial - Extended Stay Hotel 6.60 26.39 * * * ** Residential 8.19 32.78 * * * ** Gateway Phase 4 21.94 87.78 * * * ** Total 176.51 706.06 * Sanitary Sewer Impact Analysis "Bert Wheeler, Inc. 8.741 & 4.242 Acre Tracts ", Kling Engineering & Surveying, August, 1997. ** Wastewater Design Report "University Town Center, Phase 1 ", Kling Engineering & Surveying, December, 2004. * ** Wastewater Design Report "University Town Center, Phase 2 & 3 ", Kling Engineering & Surveying, May, 2005. * * ** Water & Sanitary Sewer Report "M.D.W. Centre (Fully Developed) Commercial Development, 1200 University Drive East, College Station, Texas ", Rabon Metcalf Engineering, January 23, 2006, Rev. April 5, 2006. ***** Wastewater Design Report Gateway Phase 4 ", Kling Engineering & Surveying, November, 2006. WASTEWATER DESIGN REPORT Gateway Phase 3 4 The minimum slope in the existing 12" PVC sanitary sewer line is 0.46 %. This allows a full flow capacity of 1,084.50 gpm. PROPOSED DEMAND AVAILABILITY ANALYSIS: The area of Gateway Phase 3 which is available for development is composed of approximately 4.0 acres of open commercial zoned property. The remaining portion of the property lies within the floodway of an unnamed tributary to Burton Creek, or is not accessible. The proposed site improvements at this time are to be served internally by one 8" sanitary sewer line that connects to the existing 12" PVC sanitary sewer line. The following Table 2 shows the downstream leg of the proposed 8" sanitary sewer line, its capacity, and the acreage served upstream. To determine the flowrates for the project area, Method 2 - Land Use Determination, was used as described in the B /CS Unified Design Guidelines for Sanitary Sewer (see Appendix 2 - "Design Parameters "). Table 2 SS Line Size (in.) Slope ( %) Capacity (gpm) Acreage Served Avg. Daily Flow (gpm) Peak Hourly Flow (gpm) 1 8 0.50 383.00 4.0 4.17 16.68 16.68 12" Line Total 180.68 722.74 *Refer to exhibit for line locations The above Table 2 shows that the proposed 8" sanitary sewer line has sufficient capacity for flows from the proposed Gateway Phase 3 commercial subdivision. As previously stated, the existing 12" line was analyzed at the downstream line segment with the least amount of slope. The following Table 3 shows the total flow in the downstream 12" PVC segment of evaluation. Table 3 The above Table 3 shows that the existing 12" PVC sanitary sewer line has capacity to handle the increase in flow from Gateway Phase 3. The calculations also show that there is additional capacity remaining in the existing 12" sanitary sewer line. WASTEWATER DESIGN REPORT Gateway Phase 3 Avg. Daily Flow (gpm) Peak Hourly Flow (gpm) Line Capacity (gpm) % Capacity Remaining @ Peak Hourly Flow Existing Flow (gpm) 176.51 706.06 Additional Proposed (gpm) 4.17 16.68 12" Line Total 180.68 722.74 1084.50 33.4% The above Table 3 shows that the existing 12" PVC sanitary sewer line has capacity to handle the increase in flow from Gateway Phase 3. The calculations also show that there is additional capacity remaining in the existing 12" sanitary sewer line. WASTEWATER DESIGN REPORT Gateway Phase 3 DISCUSSION OF RESULTS: The existing sanitary system immediately downstream of the proposed Gateway Phase 3 has the capacity available to handle the increased flow from the development. Additionally, the proposed 8" sanitary sewer line has enough capacity to handle the flow generated by the entire commercial development. Based on the analysis, both the proposed and existing systems have capacity to handle the increased flow. CONCLUSIONS: Gateway Phase 3 is a proposed commercial subdivision with approximately 4.0 acres available for development. The development includes an on -site public sanitary sewer system which will connect to an existing public 12" PVC sanitary sewer line. As the analysis indicates, the existing and proposed systems adequately handle the flows from the commercial development. This subdivision will have no adverse affect on the existing sanitary sewer system. WASTEWATER DESIGN REPORT Gateway Phase 3 APPENDIX 1 VICINITY MAP VICINITY Nwp KLING ENGINEERING & SURVEYING BRYAN, TEXAS ' I SITE LOCATION, lion ON ■ D •�rl� VICINITY Nwp KLING ENGINEERING & SURVEYING BRYAN, TEXAS APPENDIX 2 DESIGN PARAMETERS SANITARY SEWER FLOW RATE CALCULATIONS EXISTING SEWER DEMAND (FROM PREVIOUS REPORTS) *A* Sanitary Sewer Impact Study "Bert Wheeler, Inc. 8.741 & 4.242 Acre Tracts ", Kling Engineering & Surveying, August, 1997. *B* Wastewater Design Report, "University Town Center, Phase 1 ", Kling Engineering & Surveying, Decemeber, 2004. *C* Wastewater Design Report, "University Town Center, Phase 2 & 3 ", Kling Engineering & Surveying, May, 2005. *D* Water & Sanitary Sewer Report "M.D.W. Centre (Fully Developed) Commercial Development, 1200 University Drive East, College Station, Texas ", Rabon Metcalf Engineering, January 23, 2006, Rev. April 5, 2006 *E* Wastewater Design Report, "Gateway Phase 4 ", Kling Engineering & Surveying, November, 2006. PROPOSED SEWER DEMAND COMMERCIAL AREA CONTRIBUTING 4.0 ACRES PERSONS /ACRE 30 USAGE 50 GPD /PERSON PROP. 8" SS LINE AVG. DAILY PEAK HOURLY REPORT 4.17 (GPM) (GPM) REFERRAL POST OAK FOREST 4.99 19.97 *A* MCALISTER'S DELI 0.78 3.12 *B* UNIVERSITY TOWN CENTER PH. 1 3.40 13.60 *B* HOMEWOOD SUITES 5.76 23.06 *C* VERANDA CONDOMINIUMS 7.50 30.00 *C* CEDARCREEK CONDOMINIUMS 13.96 55.83 *C* HAWTHORNE SUITE (QUALITY SUITES) 16.88 67.50 *C* TOWNHOUSES, DUPLEXES, AND GRAND OAKS 13.33 53.33 *C* UNIVERSITY TOWN CENTER PH. 2 & 3 30.21 120.84 *C* M.D.W. CENTRE 28.00 112.00 *D* COMMERCIAL 0.63 2.50 *E* COM- OFFICE 1.77 7.08 *E* COM -HOTEL 12.57 50.28 *E* COM -EX. HOTEL 6.60 26.39 *E* RESIDENTIAL 8.19 32.78 *E* GATEWAY PHASE 4 21.94 87.78 *E* TOTAL: 176.51 706.06 *A* Sanitary Sewer Impact Study "Bert Wheeler, Inc. 8.741 & 4.242 Acre Tracts ", Kling Engineering & Surveying, August, 1997. *B* Wastewater Design Report, "University Town Center, Phase 1 ", Kling Engineering & Surveying, Decemeber, 2004. *C* Wastewater Design Report, "University Town Center, Phase 2 & 3 ", Kling Engineering & Surveying, May, 2005. *D* Water & Sanitary Sewer Report "M.D.W. Centre (Fully Developed) Commercial Development, 1200 University Drive East, College Station, Texas ", Rabon Metcalf Engineering, January 23, 2006, Rev. April 5, 2006 *E* Wastewater Design Report, "Gateway Phase 4 ", Kling Engineering & Surveying, November, 2006. PROPOSED SEWER DEMAND COMMERCIAL AREA CONTRIBUTING 4.0 ACRES PERSONS /ACRE 30 USAGE 50 GPD /PERSON PROP. 8" SS LINE PROP. AVG. DAILY GPM PROP. PEAK HOURLY GPM 1 4.17 16.68 LINE CAPACITIES AVERAGE DAILY DEMAND REMAINING PROPOSED CAPACITY CAPACITY 8" SS LINE SLOPE ( %) (GPM) (GPM) (GPM) 1 1.00 4.17 542.00 537.83 PEAK HOURLY DEMAND REMAINING PROPOSED CAPACITY CAPACITY 8" SS LINE SLOPE ( %) (GPM) (GPM) (GPM) 1 1.00 16.68 542.00 525.32 COMBINED EXISTING AND PROPOSED DEMANDS AT SEGMENT OF EVALUATION EXISTING 12" PVC @ 0.46% AVERAGE DAILY DEMAND REMAINING TOTAL FLOW CAPACITY CAPACITY LINE SLOPE ( %) (GPM) (GPM) (GPM) EXISTING 12" 0.46 180.68 1084.50 903.82 PEAK HOURLY DEMAND REMAINING PROPOSED CAPACITY CAPACITY LINE SLOPE ( %) (GPM) (GPM) (GPM) EXISTING 12" 0.46 722.74 1084.50 361.76 EXISTING 12" Worksheet for Circular Channel Project Description Project File h: \engineering projects \gateway phase 3 \sanitary sewer \sanitary.fm2 Worksheet EXIST 12" SAN Flow Element Circular Channel Method Manning's Formula Solve For Full Flow Capacity Input Data Mannings Coefficient 0.013 Channel Slope 0.004600 ft/ft Diameter 12.00 in Results Depth 1.00 ft Discharge 1,085 gal /min Flow Area 0.79 ft 2 Wetted Perimeter 3.14 ft Top Width 0.00 ft Critical Depth 0.67 ft Percent Full 100.00 Critical Slope 0.007518 ft/ft Velocity 3.08 ft/s Velocity Head 0.15 ft Specific Energy FULL ft Froude Number FULL Maximum Discharge 2.60 cfs Full Flow Capacity 2.42 cfs Full Flow Slope 0.004600 ft/ft FlowMaster v5.12 10/09/07 Page 1 of 1 09:35:59 AM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755 -1666 SANITARY SEWER LINE "1" Worksheet for Circular Channel Project Description Project File h: \engineering projects \gateway phase 3 \sanitary sewer \sanitary.fm2 Worksheet 8" SANITARY Flow Element Circular Channel Method Manning's Formula Solve For Full Flow Capacity Input Data Mannings Coefficient 0.013 Channel Slope 0.005000 ft/ft Diameter 8.00 in Results Depth 0.67 ft Discharge 383 gal /min Flow Area 0.35 ft 2 Wetted Perimeter 2.09 ft Top Width 0.00 ft Critical Depth 0.44 ft Percent Full 100.00 Critical Slope 0.008483 ft/ft Velocity 2.45 ft/s Velocity Head 0.09 ft Specific Energy FULL ft Froude Number FULL Maximum Discharge 0.92 cfs Full Flow Capacity 0.85 cfs Full Flow Slope 0.005000 ft/ft FlowMaster v5.12 10/26/07 Pa e 1 of 1 11:00:55 AM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755 -1666 9 C) 0 o N t0 V � O C O O p N O O W O W O O w w i 0 � 0 O L" O W W C O O N � rn •T� 1ji v O O 1 A W _ O o o N T — ° N o 4� rn ao O w o ° W N O to O O O CA O p0 ( N WO ? � OD O p O V �O O 0 N CD � O o A N C1 N w { Z LZ 0 0 o 0 ON 5 n o .-a / � o N .�e� p N cn co , yo, Fs oo a G ° ° o C> co oy _ Z ° co � c `" v o w c zN. 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