Water Well Journal
Issue link: http://read.dmtmag.com/i/465664
in the well should be started immedi- ately upon shutdown of the test pump and taken at specified time intervals thereafter until water levels in the well have recovered to within 90% of the static water level. For well performance tests, two tests are commonly used: the step-discharge test and the constant rate test. 1 The ANSI/NGWA Water Well Construction Standard recommends the step-dis- charge well performance test should have at least four steps at rates between 50% and 110% of the design capacity of the newly constructed well. The first step rate should be run until the draw- down within the well stabilizes in a trend that is apparent over a logarithmic time interval, while the duration of each subsequent step should be about the same time duration as the first step. Based on observations and data collected during the step rate test, the constant rate well performance test is conducted at a set discharge rate and should be conducted a minimum of 24 hours. Whenever the specified limits to determine peak and long-term capacity and well efficiency of the performance test cannot be met, the testing should end. Retesting should never be started until the water levels in the pumping and observation wells have returned to static conditions. The ANSI/NGWA Water Well Con- struction Standard recommends proper documentation of data collected during the well performance test (WPT). Even though this may seem straightforward, it is surprising the amount of times this simple step is taken for granted . . . until testing has to be done again because what occurred in the field cannot be guessed at back at the office. Time is a client's money. Other use- ful information that should be docu- mented as part of the WPT includes the physical data pertaining to the well itself (location, pump attributes, construction details, etc.) and testing data (hydraulic head, discharge, and water quality data, weather, etc.). Data Recording It's important to provide well drilling field data and information so a hydroge- ological as-built condition of the newly drilled well is recorded. This is the well completion report. Sometimes there is other equipment or appurtenances installed around the well (municipal wells with pipes and disinfection/treatment facilities). The standards subcommittee focused on recording those field parameters that are closely associated with the initial drilling of the well within the bored hole and the WPT. The parameters to be in the well completion report are recorded during all phases of well construction. For ex- ample, Section 7, summarized earlier in this article, describes the WPT field- related data related to determining the hydraulic performance of the well. Many sample the well for quality during and immediately after construction of the well. Section 10 describes the water sampling and analyses that shall be per- formed during and after the construction of the wells. The parameters to be recorded when eventually the well is decommissioned can be found in Section 11.8 of the standard. The parameters specifically identi- fied in Section 8 of the standard to be included in the well completion report (WCR) are directly related to the well location and ownership, and the physi- cal/hydrogeological characteristics of the well. The parameters identified in Section 8 were not meant to be com- pletely exhaustive of all the well con- struction data to be reported, but rather the most important summary. The WCR must be organized and filed in a format most useful to its in- tended user(s). Some of the identified parameters may be required to be filed with regulatory agencies that permitted the well. Please be aware that some jurisdictions regard the statutory filed WCR as confidential. Many jurisdictions have standardized the format for reporting and filing well completion data to that respective juris- diction. For example, California is de- veloping a web portal for completing WCRs online by summer 2015. Please note the jurisdictional WCR may include some or more than all of the parameters identified in Section 8 of the ANSI/NGWA Standard. There could be changes to regulatory WCR requirements since the publica- tion of the ANSI/NGWA Standard, so users are encouraged to consult prevail- ing regulations and report those other specific parameters are mandated by the permitting agency even if the parameter is not explicitly stated in Section 8. Some well owners may request addi- tional data to be reported as part of the contract specifications. In general, the parameters listed in Section 8 can be grouped into the fol- lowing categories: • Well ownership and purpose of well • Well location including reference elevation data • Driller information and drilling method • Well construction data including cas- ing, screen ,and grouting information • Well performance testing data. Some of those data are collected or provided by the well own er and others by the driller. The usual practice is for the driller to complete and file the DACUM Codes To help meet your professional needs, this article covers skills and competen- cies found in DACUM charts for drillers and pump installers. DO refers to the drilling chart. The letter and number immediately following is the skill on the chart covered by the article. This article covers: DOB-1, DOC-5, DOG-6, DOG-7, DOG-8, DOJ-1, DOJ-2, DOK-8 More information on DACUM and the charts are available at www.NGWA.org. 34 March 2015 WWJ waterwelljournal.com STANDARD from page 33 1 Water discharged during either testing ref- erenced above should always be conveyed away from the test and observation wells, especially if there is any potential for local recharge of the well being tested. Time is a client's money. Other useful information that should be documented includes the physical data pertaining to the well itself and testing data.