Water Well Journal
Issue link: http://read.dmtmag.com/i/573697
around 1000 ppm, and hard- ness was 22 to 30 grains. "The water quality was questionable," reports Doug Neibauer of the South Central Regional Water District. "It passed all the testing require- ments, but it was a somewhat difficult water to distribute." Second, flow rates needed to be about 2400 gallons per minute in order to serve the district's 3500 hookups. The district also expected to put the system on the 300- foot-wide parcel of land it had used for the preexisting well site and water treatment plant. Furthermore, it wanted to look into the possibility of riverbed filtration, which has been shown to improve the taste and smell of the water in addition to removing some pollutants, such as industrial chemicals. Lastly, all of the construc- tion had to cost less than $1.4 million. Reaching the "Sweet Spot" Finding a cost effective method of reaching high quality water at the appro- priate yield was a challenge, says Joe Bichler, manager of Bartlett and West's Bismarck office. Engineers rejected vertical wells, horizontal directionally drilled wells, horizontal collector wells, traditional river intake, and an infiltra- tion gallery. Angled wells drilled at 15° under the Missouri River, though, met all of the district's criteria. Altogether eight wells, consisting of one 12-inch test well, a 6-inch monitoring well, two 12-inch angled wells, and four more angled wells, will yield 2400 gpm and cost about $1.2 million in construction costs. In this case, an angled well could best reach a shallow part of the aquifer where it is influenced by the Missouri River. The river's water quality is good, but the water levels are too low to sup- port a traditional river intake system. The next best thing to drawing from the river was to draw from the part of the aquifer closest to the river. Although horizontal wells could also reach this "sweet spot," the yield wasn't quite what the district needed and development of the wells concerned engineers. Installing the wells at an angle in- creased the screen length, which also in- creased the wells' yield, explains Dave Traut, MGWC, of Traut Wells Inc. in Waite Park, Minnesota, the company contracted to drill the wells. Higher yields mean less wells are needed, thus reducing construction and maintenance costs for the district. WWJ October 2015 65 Twitter @WaterWellJournl Traut Wells installs the 40 slot muni-pak well screen for the third well at a 15° angle. The angle allows them to increase the screen's length, which in turn increases the well's yield. STRAWN continues on page 66 Exceeding Drilling Expectations, Daily. s l l i r t d s e n fi e th r fo e c r u o s r u o Y e d i w d l r o w e l b a l i a v a l a c i n h c te o e G l ta n e m n o r i v n E l a m r e th o e G l xpectations, Daily. a m r e th o e G l l e W r te a W / M n o ti c u tr s n o C r e g u A y r ta o R c i n o S s k c u tr T P C s r e m m a h to u A m p i u q e ty l a i c e p S g y. n i n i s t n e m 3 6 4 4 . 4 0 4 . 0 0 8 . 1 m o c . s e i g o l o n h c te l r a m Exceeding Drilling Expectations, Daily.