Laserfiche WebLink
po ... <br />[ <br />[ <br />[ <br />[ <br />[ <br />[ <br />L <br />Estimate the land area recuired for retention ponds <br />-' Assume 3 :1 side slopes <br />Assume 2 feet free board when pond is full <br />Assume 10 foot water depth <br />Area 0 @ 1 .55 acres <br />Surface area full 67 .518 ft2 <br />Surface area empty 47,500 ft2 <br />Average su rface area 57,509 ft2 <br />Volume 575,090 cu. feet <br />4,301,673 1 gallons , <br />Case 11/ requires more land area <br />Increase land area to 2 .32 acres move 100 feet to west) <br />I <br />Surface area full 101 ,059 ft2 <br />Surface area empty 91,000 ft2 <br />Average surface area 96,030 ft2 <br />Volume 960,296 cu. ft <br />7 ,183.014 gallons <br />Actual land area required Is somewhat less. <br />1 -.l. <br />Estimate annual volume of runoff hauled In a 20-year penod <br />1 <br />.}ase I Average Is zero . I <br />Assume 10 years no watE,r Is hauled. <br />Every 5 y.ears llTecipitation is 17.4 Inches 4 events 2.8 inches <br />Every 10 years precipitation Is 19.5 inches 2 events 4.9 <br />Every 20 years precipitation is 21 .4 inches 1 event 6.8 <br />Assume 3 additional events at haH the 5 year 3 events 1.4 <br />Total 15.9 inches <br />VoIume= 14.346;161 19a1lons for 20 year period <br />Annual average= 717,308 gallons <br />Case" Same assumptions as CeLSe I for calculating 20 year volume <br />1 <br />Volume" 7.110.480 galloM for 20 year period <br />Annual average= 355.524 gallons <br />I <br />Case " Haul runoff even in average year <br />Annual averaae= 3,054.518 aallons <br />1 <br />FN: dtr/a:\WATERBAL.XLS Page 4 of 5 Printed: 8131/94 3:46 PM