Month: April 2022

When you turn on the tap to get a drink, do you wonder where your water comes from? If you live in a city, the answer is probably the city’s water grid. But if your home is on well water, your refreshing drink comes straight from the depths of the earth. There are many uses of groundwater that we often take for granted.

Groundwater is one of our most valuable resources, so we should pay attention to how we use it. Today, we’re facing a trend of groundwater depletion that could put human life at risk. So what is groundwater depletion and what can we do to prevent it?

The Problem: Groundwater Depletion

Water is a limited resource. While more than 70 percent of our planet is covered in it, only three percent of that water is drinkable — and two percent of that is frozen in our polar ice caps. Much of the water we drink is pumped up from beneath the ground. One of the primary uses of groundwater is providing drinking water: for 37 percent of urban households and 90 percent of the water consumed by rural households.

Groundwater is becoming scarce in certain areas around the world. The underground aquifers that store this drinkable water are beginning to run dry. The water cycle naturally replenishes the aquifers — rainwater trickles down through the substrate and is purified along the way — but we’re pumping the water out faster than it can refill.

This kind of groundwater depletion plays a significant role in the fact that one out of every nine people in the world doesn’t have access to clean drinking water. Water shortages are becoming more common — Cape Town, South Africa, almost ran out of water entirely in 2016. Over pumping lowers the water table and increases the cost of water, and can even affect the level of local lakes and rivers.

Pumping isn’t the only threat to these natural water sources. The growth of “fracking” — the colloquial name for hydraulic fracturing — also threatens water supplies. Fracking works by forcing water or another fluid through a narrow opening to fracture the rocks that contain natural gas. Miners can harvest the gas, but the water or liquid that they used for the fracturing is contaminated and can leak into natural groundwater sources. This limits the uses of groundwater because, once it has been contaminated, it is no longer considered potable.

What can we do to prevent groundwater depletion and contamination?

Focus on Native Landscaping

It’s tempting to find the most beautiful and exotic plants you can to decorate the exterior of your home, but this isn’t the best idea. Non-native plants often come from rain forests and other areas where precipitation is plentiful. If your home doesn’t get as much rain as the Amazon, you’ll end up wasting a lot of water to keep them alive.

Focus on native plants instead of exotic ones. They’ll look just as beautiful, and you won’t have to waste all your time — and all of your water — trying to keep them alive in an environment that is so unlike their own.

Fix Your Leaks

Leaky faucets are annoying, but they’re also one of the biggest water-wasters in the world. One valve, dripping once per second, leaks roughly one-quarter of a milliliter with every drop. It might not sound like much, but it adds up quickly. That single quarter-milliliter becomes 86,400 drips per day, for a total of five full gallons of water. That’s 2,028 gallons of water down the drain every year.

Follow Watering Restrictions

We all love having a green lawn or a lush garden, but watering during the middle of the day means you’ll need more water to keep your plants alive. Once the sun reaches its peak, much of the water you’re using evaporates instead of soaking into the ground to reach the roots of the plants that need it. That is why many cities regulate watering. You’re only allowed to irrigate your plants late in the evening or early in the morning, when evaporation is no longer a problem.

Watering restrictions become even stricter during the dry months. Pay attention to these restrictions so you’re not wasting water unnecessarily. At the same time, pay attention to the weather — you don’t need to water your plants if it rained during the day!

Don’t Dump

Many of the chemicals we use every day are hazardous to local water tables. Fertilizers, pesticides and even cleaning materials can end up in a raindrop that makes its way down into the aquifer. This contamination then infiltrates your drinking water.

Pay close attention to the chemicals in and around your home. Choose natural alternatives whenever possible. Don’t dump any chemicals outside your house. Even if stormwater runoff isn’t a problem, these chemicals can be dangerous to local plants and animals.

Conserve Water

The average American household uses 300 gallons of water each day. In 2015, the United States alone used 322,000 million gallons of water per day. Every home and business can take steps to conserve water, from shutting off the water while brushing your teeth to taking shorter showers and upgrading your fixtures to low-flow alternatives.

If every household reduced their water use by just 50 gallons a day — which you can do by replacing your old toilet with a low-flow model — we could save millions of gallons of water and prevent groundwater depletion. Every little bit helps, but it will take a lot of homes making small changes for it to add up into an effective transition.

Protecting Groundwater Is a Shared Mission

Groundwater is one of our most valuable resources and it’s becoming scarcer every year. Every household and business needs to do everything they can to reduce each of their uses of groundwater, from fixing leaky taps to reducing use or watering intelligently. We have a limited amount of drinkable water on our home planet, and once it runs out, human life will quickly follow it into the abyss.

Clean, safe groundwater is one of our most valuable and essential resources on this planet. It is the duty of groundwater professionals to protect this valuable resource for future generations. Good well construction practices, including grouting and/or sealing water wells from the top of the well screen all the way to the surface, ensure no pathways for surface contamination to the water we count on. This practice also ensures that poor aquifers don’t comingle with good production aquifers.

Groundwater contamination can come from many sources. These sources include:

• Industrial waste
• Chemical and hydrocarbon contamination from refinery operations or leaky tanks
• Pesticides, fertilizers and/or animal waste runoff from agricultural applications
• Septic systems
• Contaminated aquifers that are above desirable aquifers

Many states require contractors installing domestic water wells to grout or seal only the upper 10 to 20 feet of the well. This leaves a void (the annular space below the sealed area) that can potentially serve as a pathway for contamination to enter the aquifer. Ideally, after the water well is drilled and the casing and gravel pack are in place, a tremie line is lowered to just above the gravel pack/well screen area. Grout is pumped through the tremie line to displace drilling fluid and fill the annular space.

While working in the northern Baja California area of Mexico, I was asked to look at some large irrigation wells. The issue was that the steel casing was being destroyed in as few as five years from installation. Before going out into the field to inspect the well sites, we stopped in at the drilling contractor’s facility. There we found everything, including drill pipe, tooling and casing, laying on the ground (a source for iron bacteria). It was apparent as we approached the first well site that the well was pumping into a concrete ravine; the ravine collected the water and distributed it to many agricultural fields in the area. At the water line, a bright red rust line was visible and the water smelled of rotten eggs (a tell-tale sign of iron bacteria). The 400+ irrigation wells were over 800 feet deep. The annular space was not grouted from the well screen to the surface, and therefore, one can assume that everything from fertilizers to pesticides being sprayed on the crops was eventually finding its way into the aquifer used to supply water to the fields. It is also safe to assume that iron bacteria picked up by tooling, drill pipe and casing lying on the ground was being transferred back into a nutrient-rich environment. Fertilizers were finding their way into the aquifer (high nitrogen and phosphate levels could be detected in the water), resulting in the rapid failures to the steel casing.

Another example of poor grouting and sealing practices that this writer personally witnessed was on a large geothermal heating and cooling installation. The project was at a military base on the southern coast of South Carolina. Hundreds of geothermal loops were installed to a depth of 200 feet and, to comply with state grouting and sealing regulations, the annular space was sealed to a depth of 20 feet from the surface. Unfortunately, the holes penetrated a saltwater aquifer that was above a good freshwater aquifer, which was a major water source for a large metropolitan area. The open geothermal holes became a pathway for the denser saltwater to easily migrate down into the good fresh water aquifer and became a source of contamination. To make matters worse, the geothermal heating and cooling systems did not function correctly because the holes lacked the thermally enhanced grout needed to correctly exchange temperature between the loops and the surrounding ground. The properly installed geothermal grout would also have prevented the commingling of aquifers and guarded against surface contamination.

The solution to the above-mentioned scenarios is good grouting and sealing practices. Drilling professionals must also be knowledgeable in selecting the proper grout for their applications. For example, a 20-percent high-solids bentonite grout may work well for areas where the ground stays moist, but in areas with large vadose zones, a 20-percent solids bentonite grout (i.e., 20 percent solids/80 percent water) can desiccate (dry out and shrink). The grout will not adequately rehydrate to protect the wells and aquifers from contamination. In the vadose zone, a higher-solids-content grout, such as a grout/sand mixture, may be required.

A grout also must be significantly heavier than the drilling fluid that it will displace in order to properly seal the annular space. Years ago, I heard a contractor in southern Florida complain about experiencing grout failure with 20-percent solids bentonite grout. In fact, they were drilling with a high-solids drilling fluid that weighed 11.5 pounds per gallon and they were trying to displace with grout that weighed only 9.5 pounds per gallon. Naturally, the lighter bentonite grout quickly floated to the surface. It was like oil in water; the result was an inadequately grouted water well where an undesirable upper water table that was high in iron migrated and commingled with a good aquifer.

Passing on safe drinking water to future generations depends on good well construction practices. This includes grouting and/or sealing water wells from the top of the well screen all the way to the surface. This is the only way to ensure that the wells we use to obtain clean and safe drinking water are not the pathways for contamination.