Water Well Journal
Issue link: https://read.dmtmag.com/i/557876
Assuming a 75-year well life and standardizing on pumping rate, utiliza- tion, pump/motor efficiency, pump equipment replacement, well rehabilita- tion requirements, and the observed well life of each steel material type, the as- sessment provided the low carbon steel design will require replacement in 25 years, the HSLA steel design will require replacement in 40 years, and the stainless steel well will not require replacement during the 75-year life assessment. From these assumptions, the 75-year well life parameter will require three low carbon steel well costs, two HSLA steel well costs, and one stainless steel well cost. From this economic analysis, the full 75-year life cycle cost of each well design is: Low carbon steel = $16.7 million HSLA steel = $14.5 million Stainless steel = $12.4 million Based on the initial well cost calcu- lated, the recovery cost of a stainless steel-constructed well compared to a low carbon steel design is approxi- mately six years. In summary, the desire for longer asset life and more efficient operations are being pursued throughout all areas of the water industry. As shown in the McEllhiney analysis, it is not unreason- able to target a 75-year well life consid- ering proper material selection. However, as municipal budgets evaluate asset costs, it is paramount the complete life cycle cost, based on site specific factors, are revealed and assessed. References Glotfelty, M.F. 2012. Life-Cycle Eco- nomic Analysis of Water Wells— Considerations for Design and Construction. Schnieders, J.H. 2009. Change Is Good—Making changes in well design or operation can lead to increased well life. Water Well Journal 63, no. 11: 29-32. Schnieders, M. 2013. Engineering a Better Gravel Pack. Presented at NGWA Groundwater Expo, December 3-6, Nashville, Tennessee. U.S. Environmental Protection Agency. 1976. Manual of Water Well Construction Practices. EPA-570/ 9-75-001. U.S. Geological Survey. 1963. Filter Pack and Well Screen Design. OFR 63-60. Roger Miller serves as a senior consultant for Water Systems Engineering. His work over the past 30 years has involved research and development, analytical procedures, site assessment, and project oversight in the groundwater industry. Martha Silks, PG, is an associate with Leggette, Brashears & Graham Inc. and has been designing water wells in both unconsoli- dated and consolidated forma- tions for close to 30 years. She brings a practical viewpoint on well design and construction. WWJ CRITERIA from page 23 waterwelljournal.com 24 September 2015 WWJ e: n mor ear L . d o eliho our liv ts y ec ot pr er t a oundw ting gr ec ot r P . n a c y e h tion t tamina on c y t an ec r or t or c en ev o pr tion t ac ing ak Tak • o them y apply t which ma onsidering C • ells ly abandoned w oper and impr , ems st tioning septic sy , malfunc es household substanc dous oper disposal of hazar tion such as impr tamina on c er t a oundw r table g en ev causes of pr wledging no ck A • y: T b C o A omers t our cust ge y Ur GWD Y g/P A.or NGW WA.or .