Corporation of Corporation of Corporation of Corporation of Shepherdstown Water Storage Shepherdstown Water Storage T T Tanks Project Tanks Project k P k P j j t t Chapman Technical Group Chapman Technical Group March 29, 2012 March 29, 2012 March 29, 2012 March 29, 2012
Existing Tanks Existing Tanks 500 000 Gallons 500 000 Gallons 500,000 Gallons 500,000 Gallons Each Each for Total of for Total of 1 000 000 Gallons 1 000 000 Gallons 1,000,000 Gallons 1,000,000 Gallons
Storage Tank Deficiencies Storage Tank Deficiencies • Low water pressures in areas located near the Low water pressures in areas located near the tank when tank levels drop below 70.5’. tank when tank levels drop below 70.5’. • Existing Storage Tanks have a limited usage of Existing Storage Tanks have a limited usage of g g g g g g approximately 20% of the tanks volume approximately 20% of the tanks volume • Inadequate turnover in the tanks increases water Inadequate turnover in the tanks increases water age in the tanks. age in the tanks. age in the tanks. age in the tanks. • This problem is a major contributing factor in the This problem is a major contributing factor in the system not meeting Total Trihalomethanes system not meeting Total Trihalomethanes (TTHMs) and Haloacetic Acids (HAA5s). (TTHMs) and Haloacetic Acids (HAA5s). (TTHMs) and Haloacetic Acids (HAA5s). (TTHMs) and Haloacetic Acids (HAA5s). • Due to limited useable tank volume, the system Due to limited useable tank volume, the system does not provide adequate fire protection or 2 does not provide adequate fire protection or 2- -day day storage as required by the WV Bureau of Public storage as required by the WV Bureau of Public storage as required by the WV Bureau of Public storage as required by the WV Bureau of Public Health Design Standards. Health Design Standards.
Distribution System Modeling Distribution System Modeling Distribution System Modeling Distribution System Modeling • Utilized Existing EPANET Model Utilized Existing EPANET Model • Mapped Existing Water System on AutoCAD Mapped Existing Water System on AutoCAD to verify piping as shown in the model and to verify piping as shown in the model and to verify piping as shown in the model and to verify piping as shown in the model and revised as needed revised as needed • Verify and adjust node elevations based on Verify and adjust node elevations based on Verify and adjust node elevations based on Verify and adjust node elevations based on aerial mapping aerial mapping • Verify tank operating levels & water usage Verify tank operating levels & water usage • Adjusted Demand Factors in model to Adjusted Demand Factors in model to represent actual usage within in the system represent actual usage within in the system
Tank Volume Calculations Tank Volume Calculations Max Daily Usage = 559,814 GPD Max Daily Usage = 559,814 GPD Two (2) Day Storage = 2 x 559,814 gallons = Two (2) Day Storage = 2 x 559,814 gallons = ( ) ( ) y y g g g g 1,119,628 gallons 1,119,628 gallons Future Usage Future Usage - - Increase in Customers @ 2.8% Annual Increase in Customers @ 2.8% Annual Increase Increase Increase Increase Future Usage (2.8% for 10 years) = 178,050 gallons Future Usage (2.8% for 10 years) = 178,050 gallons Fire Flow (2 hrs) = 500 GPM x 120 minutes = 60 000 Fire Flow (2 hrs) = 500 GPM x 120 minutes = 60 000 Fire Flow (2 hrs) = 500 GPM x 120 minutes = 60,000 Fire Flow (2 hrs) = 500 GPM x 120 minutes = 60,000 gallons gallons Total Volume Required Total Volume Required 60,000+ 1,119,628 Total Volume Required- 60,000+ 1,119,628 = Total Volume Required 60,000+ 1,119,628 = 60,000+ 1,119,628 1,357,628 gallons 1,357,628 gallons Use Two (2) 700,000 Gallon Tanks Use Two (2) 700,000 Gallon Tanks
Tank Scenario Tank Scenario 47 psi 38 psi SHEPHERDSTOWN 89’ 30 30 psi i 70.5 ’ 31 psi 79 2% of 79.2% of Tank is Currently Unusable
Tank Construction Tank Construction
Water Storage Improvements Water Storage Improvements Water Storage Improvements Water Storage Improvements • Increased Water Pressure from 25 psi to 44 Increased Water Pressure from 25 psi to 44 Increased Water Pressure from 25 psi to 44 Increased Water Pressure from 25 psi to 44 psi in the system located adjacent to the psi in the system located adjacent to the WSTs WSTs • Increased water usage in the Tanks Increased water usage in the Tanks – – 35% 35% to 40% to 40% • Provide 2 Provide 2- -day storage day storage • Provide adequate fire storage Provide adequate fire storage • Tanks will include a mixing system to Tanks will include a mixing system to improve water age and thus reducing the improve water age and thus reducing the formation of TTHMs and HAA5s formation of TTHMs and HAA5s
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