Source Approval
“Water, Water every where; Nor any drop to drink.” –Samuel Coleridge, The Rhyme of the Ancient Mariner
Every aspect of your water system is affected by your source. Therefore, having a properly designed source and pumping system is essential in operating a sustainable water system.
The majority of sources in the state of Washington are groundwater wells. We have developed an efficient system for developing source approval reports. Most source approvals are simple and straightforward projects. We also have extensive experience with more difficult wells: low production, complicated controls, and difficult hydro-geology.
Every spring source requires a unique approach and design. We enjoy the challenges associated with a spring design: to make the spring source as sanitary as possible while maximizing production with a simple and inexpensive approach. We have successfully re-designed several delapidated spring collection systems with extremely satisfied clients.
Surface water systems require the most extensive on-going operational, monitoring, and maintenance considerations. Again, the resources available to the water system need to dictate how the design is executed. One of the most important elements of a surface water design is how the surface water is collected and pre-treated. Spending a little extra money on a quality collection and/or pre-treatment system can save a system huge amounts of time, hassle and money over the life of the system.
Well Approval Process (other sources follow a similar process)
The first step in source approval is to determine your need. This gives the engineer and contrator goals to attain. What is the absolute minimum flow needed? At what point will we no longer need storage (or additional storage)? What water quality parameters are we expecting?
The next step is to meet with your contractor and/or engineer and choose a wellsite. Once a site is chosen, then a wellsite inspection form is completed and sumitted to the appropriate regulatory agency (usually the County Health District) Once the wellsite is approved, then the well is drilled and the appropriate pump tests and water quality samples are conducted.
The engineer can now complete the source approval report. Often times in reliable aquifers, the engineer can assist the contractor in selecting a test pump that can then be left as the permanent pump. This saves the owner the cost of pulling and setting an extra test pump.
The report is submitted to DOH; comments are received and addressed; and the report is approved. Once approved, the rest of the construction can be completed. Finally, the engineer conducts a final inspection and the source can be put “on-line.”
Groundwater Under the Influence of Surface Water (GWI)
Wells with an open interval less than 50 feet and located within 200 feet of surface water are considered potential GWI sources. All Springs are considered potential GWI sources. In order to make a determination if the well is GWI, the following steps are taken:
Conduct Microscopic Particulate Analysis (MPA) during both the wet and dry seasons. It is extremely important that the MPA tests conducted are representative of the source itself and not contaminated by poor construction of a well, springbox, or sampling hardware.
If the samples results show a low risk, your system has two choices: accept hydraulic conductivity with surface water and install continuous disinfection meeting CT6, or perform temperature, pH, and conductivity monitoring weekly for one year to either establish or negate hydraulic conductivity. If the hydraulic conductivity is negated, then the process is over. If it is established, then disinfection is required.
If one of the MPA samples includes a “high risk” result, then the souce is designated GWI and must meet surface water requiements.
If one or both MPA sample yields a “moderate risk”, then additional sampling and testing is required to determine if the source is GWI.
Wellfield Designation
If your water systems have multiple wells in close proximity withdrawing from the same aquifer, they may be elidgible for wellfield designation. By being designated a wellfield, all included wells are considered one source. This can drastically reduce your water quality sampling costs over time.
The wellfield designation process involves a simple report that is relatively inexpensive, costing much less than years of redundant samples.