Water Well Journal
Issue link: http://read.dmtmag.com/i/440561
infrastructure and the unique geology and hydrology each individual location will present. It was intended to be a simple yet concise overview of what we grout and why, and in the process of identifying that reasoning, we hoped to frame it in a manner that would allow for it to reflect the best methods and practice, in what can often be a difficult and arduous process in a diverse range of localized environments. One of the key revelations after numerous discussions on the topic prompted us to accurately define what shall be done, rather than how would one do it. With this basic premise in place, we set out to get the key points to a successful grouting program identi- fied, and to further define ways to uti- lize those concepts to help us all define what we felt was a simple yet concise methodology to allow for that program to be implemented in actual site-specific conditions. Fully understanding that grouting or sealing a given formation is nothing new, we were trying to get the most straightforward methods defined. In short, we wanted to define the finished product more so than the process of getting that finished product. When the grouting task group first met on the topic, it was quickly recog- nized there were differing opinions on how we all viewed or defined annular space. So early on we set out to define that space. When considered in context, it is actually a volumetric measurement we are trying to put into the realm of the horizontal and vertical cross sections within the well. It was determined identifying the hole size relative to the casing or liner size allowed for the best way to com- municate that space and hopefully to simplify how certain regulatory bodies viewed that interface. We all found sim- ply relating the borehole size to the largest outside diameter of the casing or coupler provided the best way to convey this standard to the many different audi- ences who may each have a slightly dif- ferent way to identify that seemingly simple reference. Once we had these initial criteria in place, we actively discussed the merits and shortcomings of different grouting mixes and materials, those associated placement methods, and how each might be used within these parameters. That discussion led us to start with the basic definition of grout and what con- ditions or applications warrant specific methods or practice. It's important to mention there was strong consensus proper grouting from the top of the production zone to the ground surface will best meet with the requirement of sealing the water well from surface contaminants and at the same time address the need to seal off any undesirable water or to separate individual confining units. After listening to the numerous sto- ries of difficulties encountered, it was quickly understood that everyone knew the importance of centralizers in the process. Everyone easily reached con- sensus that designing an adequate annu- lar space, combined with centralizers evenly distributed in the cross section, make for the only truly effective way to properly address the placement of prod- uct in the most advantageous manner possible. It's this basic premise that when casing is properly centralized, hung in suspension, and the proper grouting materials and methods are used, one will have the best means in place to allow for a successful grouting and seal- ing operation. In my opinion, this is one of the most important things to consider when designing and constructing a water well that will provide clean, safe water and add the longevity commensu- rate with our intentions to utilize the re- source. It will also allow for the much simplified and definitive abandonment protocol at such time the well has reached the practical end of its useful life. During the course of compiling the data that would ultimately become the ANSI/NGWA Water Well Construction Standard, there were numerous discus- sions on the practical aspects of prop- erly placing grout and the difficulties or benefits in using one method over another in specific situations or applications. I feel compelled to mention these task group meetings and discussions took place over a long period of time, with several Standards Development Oversight Committee reviews in the in- terim. I can safely say everyone actively involved in the process was cognizant of implications in defining a standard that did not work physically with the existing and readily available tooling, products, and dimensions already recog- nized in our industry. Everyone in- volved certainly deserves credit in fairly balancing the need to define adequate annular space for proper grouting and sealing with the availability and complexity of the products that would be used in the process. I think it speaks to the overall level of professionalism in the industry when you consider we successfully brought a large and diverse group of individuals together on a project like this. It is impressive to see—after a substantial number of meetings, discussions, public comments, and reviews—we were all able to reach consensus on a document that will help us all bring better prod- ucts and services to our customers for a long time. Todd E. Hunter, CWD/PI, is the owner of Ground Water Pump Systems in Boulder, Colorado. He is a past chair of the National Ground Water Association's Standard Develop- ment Oversight Committee and is on the NGWA Board of Directors. WWJ 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, DOB-4, DOE-16, DOH-6 More information on DACUM and the charts are available at www.NGWA.org. Twitter @WaterWellJournl WWJ January 2015 23 When casing is properly centralized, hung in suspension, and the proper grouting materials and methods are used, one will have the best means for a successful grouting and sealing operation.