WATER-SUPPLY AND STORMWATER SYSTEM DESIGN WATER-WELL ANALYSIS Determining the Drawdown for Gravity Water-Supply Well Finding the Drawdown of a Discharging Gravity Well Analyzing Drawdown and Recovery for Well Pumped for Extended Period | Source HANDBOOK OF MECHANICAL ENGINEERING CALCULATIONS _SECTION 14 WATER-SUPPLY AND STORM- WATER SYSTEM DESIGN WATER-WELL ANALYSIS Determining the Drawdown for Gravity Water-Supply Well Finding the Drawdown of a Discharging Gravity Well Analyzing Drawdown and Recovery for Well Pumped for Extended Period Selection of Air-Lift Pump for Water Well WATER-SUPPLY AND STORM-WATER SYSTEM DESIGN Water-Supply System Flow-Rate and Pressure-Loss Analysis Water-Supply System Selection Selection of Treatment Method for Water-Supply System Storm-Water Runoff Rate and Rainfall Intensity Sizing Sewer Pipe for Various Flow Rates Sewer-Pipe Earth Load and Bedding Requirements Storm-Sewer Inlet Size and Flow Rate Storm-Sewer Design Water-Well Analysis DETERMINING THE DRAWDOWN FOR GRAVITY WATER-SUPPLY WELL Determine the depth of water in a 24-in 61-cm gravity well 300 ft 91-m deep without stopping the pumps while the well is discharging 400 gal min L s . Tests show that the drawdown in a test borehole 80 ft m away is 4 ft m and in a test borehole 20 ft m away it is 18 ft m . The distance to the static groundwater table is 54 ft m . Calculation Procedure 1. Determine the key parameters of the well Figure 1 shows a typical gravity well and the parameters associated with it. The Dupuit formula given in step 2 below is frequently used in analyzing gravity wells. Thus from the given data Q 400 gal min L s he 300 - 54 246 ft m rw 1 m for the well and 20 and 80 ft and m respectively for the boreholes. For this well hw is unknown in the nearest borehole it is 246 - 18 228 ft m for the farthest borehole it is 246 - 4 242 ft m . Thus the parameters have been assembled. Downloaded from Digital Engineering Library @ McGraw-Hill Copyright 2006 The McGraw-Hill Companies. All rights reserved. Any use is subject to
