Introduction

You have found the perfect parcel of land, consulted with an architect, scheduled your builder, but now you realize you need water! Drilling can be an expensive proposition, especially in hard rock areas where the risk of drilling a dry well is high. hydroGEOPHYSICS is here to help you examine the risks, site a well location, plan the well construction, help you select a driller, and coordinate with your drilling contractor.

Is there a way to ensure that I will NOT drill a dry well?

In hard rock areas, no, but you can dramatically reduce the risk by locating the well in the most favorable geologic location that will maximize the chance of water production. How? By consulting experts in geology, hydrology and geophysics who can perform a scientific well siting.

Why not use a dowser?

Case histories and personal demonstrations of dowsers in action may seem very convincing and often are entertaining. However, when dowsing is exposed to scientific examination (controlled testing),it quickly loses its luster. "I know people who found water by dowsing!" The unfortunate explanation of dowsing's sucess is that in many areas ground water is simply hard to miss. Not so in many areas of Arizona. We also tend to remember the flamboyant success stories over the many misses. In fact, surveys conducted as far back as the 1950's show that "There is no significant difference between the percentage of successes among [the] divined wells and [the] non-divined wells." (Vogt and Golde, 1958).

How does scientific well siting improve my chances?

At hydroGEOPHYSICS, our staff includes degreed personnel with expertise in geology, hydrology and geophysics. We employ these methods to locate favorable well sites. These proven techniques have contributed to our success rate of over 90% throughout Southern Arizona. When one considers the high cost of water well drilling, especially in arid regions such as ours, our well location services offer an inexpensive way to improve the odds of hitting water. This holds especially true for those properties that are located in hydrologically difficult areas, typically where bedrock is shallow.

Is my property in a hydrologically difficult area?

We have to know where your property is located. From that, we can generally determine the aquifer type and conditions for your area. There are two types of aquifers: granular and fracture flow. Granular flow aquifers are typically encountered in alluvial basins such as the Santa Cruz (Tucson) basin. Granular flow aquifers are made up of sands and gravels through which water flows easily.

A good analogy is a bathtub full of sand and water. Placing a well anywhere in the tub will give you water in the same abundance and at the same level. Alluvial basins usually provide easy targets for well locations. Fracture flow aquifers, on the other hand, pose severe problems for well locations. An equivalent analogy is the same bathtub full of carefully and tightly stacked bricks, again with water at the same level. Placing a well in the brick-filled tub will produce water, if and only if, the well penetrates a joint between bricks (the equivalent of a fracture in bedrock).

Alluvial Aquifer	Fracture Flow Aquifer

There are two salient differences between the sand-filled and brick-filled tubs; the volume of water available and the rate at which it flows into the well. Volumetrically, the brick-filled tub will hold much less water because of the large volume of bricks that displace water. In real-world situations the water would be supplied from an outside source so that tends to mitigate the supply problem. Also, generally, in a bedock environment, fractures are so tight that water does not flow freely. The optimal situation is to encounter a fracture that is loose (has sufficient aperture) and will allow reasonable amounts of water to flow. For domestic applications the volume of available water is seldom a concern.

What well location services do you offer?

Some points to consider

One important point that we always stress is that the well locations are best scientific estimates based on what information is available and our own understanding of ground water. We wish we could guarantee success, but there always exists an inherent risk of drilling a dry well in hard rock areas. Any well sitings that we make are those that we would drill for ourselves given it were our property and our money. We tend to be on the conservative side.