Common Mistakes in Groundwater Resources Development
Barney Paul Popkin, Consultant Barney Paul Popkin is a water, wastewater, environmental and waste management consultant with over 50 years of expe-
rience in the U.S. and internationally. Mr. Popkin has an AB in Geology and MS in Hydrology. He worked as a hydrologist for several major U.S. firms a, and as an advisor and consultant to the U.S. Agency for International Development, Asian Development Bank and World Bank
There are a great many ways to damage a successful groundwater resources development program. Often well drillers, pump providers, equipment vendors, sales and service personnel, and even hydrologists are unclear that aquifer tests or pumping tests provide useful information on the transmis- sivity, permeability (hydraulic conductivity) and storativity (storage coefficient) of the aquifer, well tests provide useful information on well efficiency through its specific capacity, while pump tests provide useful information on pump perfor- mance (horsepower, flow rate, and hydraulic heads, lifts and gradients) under ideal laboratory test conditions. Pumping tests, well tests and pump tests are not the same. Word to the wise!
Here are a few ways to challenge groundwater development
that I’ve encountered during my 50+ year career in the USA and abroad.
• Siting water wells close to each other, roads, energy sources, or other conveniences rather than where the groundwater conditions are most favorable. A good rule of thumb is to provide 500 lateral feet between pumping wells. Of course, water wells could be locat- ed close together but such wells should not be pumped simultaneously or while the others are recovering their pumping-water levels to static levels.
• Siting wells within the recharging influence of soil, surface water or groundwater contaminants, such as: agricultural runoff, which produces pesticides and fertilizers; landfills and cemeteries, which produce contaminating leachate; leaking aboveground or underground fuel storage tanks or pipelines, which produce petroleum contaminants, and commercial, industrial and mining and refinery areas, which produce hazardous waste streams, etc.
• Drilling wells with mud and not developing the well to remove the mud which is otherwise a barrier to optimal groundwater-flow into the well. I like using biodegradable foams, water, and reverse rotary.
• Drilling a crooked or non-straight water well which makes it tough on a vertical shaft turbine pump. Straight-hole centering devices are readily available or constructible.
16 TPG •
Jul.Aug.Sep 2019
Figure 1 - Colleagues inspecting a drinking water well with an electrical submersible pump, peri-urban Kabul, Afghanistan.
• Completing water wells with improperly selected well screens that produce turbulent groundwater flow to the well, reducing the well’s potentially higher yield, and increasing operating costs, well and pump maintenance, repairs and downtime. Sized V-notched steel well screen is the best and most efficient, although it’s the most expensive.
• Screening too much or too little of the subsurface to supply water to the well. Too much screen is a waste- ful cost, too little diminishes the well’s potential capacity. Screening for a zone of unacceptable water quality can diminish the supplied water quality and perhaps lead to abandonment of the well.
• Installing an insufficient amount of water wells to meet demand, thus causing downtime for repairs,
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