IDAHO'S GROUNDWATER COUNCIL
Groundwater is an essential resource for Idaho, supplying over 90 percent of the state's drinking water. Groundwater is also a principal source of water for industrial, public, and rural water uses in Idaho. Idaho ranks in the top five states in the United States for volume of groundwater used, with the major use being irrigation. Because so many Idaho citizens rely on groundwater for their many needs, it is important that this resource be protected from contamination.
Groundwater is now perceived as a limited resource that is relatively easy to contaminate, and once contaminated, very difficult to clean up. Past and present efforts nationwide also have shown that tremendous costs can be incurred when cleaning up groundwater contamination, accentuating the need to prioritize prevention of contamination over clean-up. These concerns have led policymakers and citizens to coordinate their efforts to protect groundwater as one of Idaho's most valuable resources.
Because of the importance of groundwater to the people of the state of Idaho,
legislation was passed in 1989 to develop a comprehensive approach for
groundwater quality protection. The Idaho Legislature enacted the Groundwater
Quality Protection Act (GQPA) of 1989. The act called for creation of a
Groundwater Quality Council responsible for developing a Groundwater Quality Plan
(GQP) that included a Groundwater Quality Monitoring Program for adoption by the
legislature. The act required the Idaho Division of Environmental Quality (IDEQ),
the Idaho Department of Water Resources (IDWR), and the Idaho Department of
Agriculture (IDA) to assist the Council in the development and administration of
the groundwater quality plan and the monitoring program. Additionally, the act
stressed that all cities, counties, and state agencies of Idaho must incorporate
the provisions of the GQP into the administration of their programs. The GQP is a
planning document, not a set of regulations. The purpose of the GQP is to protect
groundwater quality for public use. The act specified that the plan should:
Groundwater Quality Plan. The GQP was developed as a first step in providing comprehensive groundwater quality protection for Idaho. The plan has been completed, reviewed by the public, and passed into law by recent legislation. The statewide monitoring program has already been initiated, and the evaluation of groundwater quality related programs has been completed by the GQC to be delivered to the legislature next year. The Groundwater Quality Council has requested an extension of its existence until July 1995. The backbone of the plan is prevention with emphasis on the need to anticipate potential groundwater contamination. The plan further provides agencies with direction to develop management programs and regulations and to implement groundwater quality protection strategies. The GQP is elaborated in 22 policies intended to provide an overall protection strategy.
Future issues of this newsletter will highlight groundwater quality policies and groundwater quality monitoring associated with the Groundwater Quality Plan.
WATER CONDITIONING SYSTEMS
Methods used to improve the quality of water are referred to as "treatment" or "conditioning." What is the difference? Water treatment reduces levels of harmful contaminants in the water; therefore, it deals with the health or safety of the water. For example, high levels of coliform bacteria, nitrates, arsenic, lead, and pesticides must be treated before water is safe for human consumption.
Water "conditioning" generally deals with problems that affect water taste, color, smell, hardness, and corrosivity rather than health and safety. Magnesium, calcium, iron, manganese, and silt are common contaminants that require water conditioning when they reach high levels. It is not uncommon to use both treatment and conditioning methods to improve water quality. This article covers water conditioning by filtration systems.
A broad category of systems use filtration to remove particles, undesirable
taste, odor, some organics and minerals, and some bacteria from the water.
Filtration systems fall into several categories:
Mechanical filtration. Mechanical or sedimentation filters retain debris as water passes through the filter unit. Mechanical filters are most effective for removing particles such as sand, silt, ferric iron, algae, and some bacteria. Their effectiveness depends on the particle size and the exit clearance of the filter.
Activated carbon filtration. Activated carbon filtration is a common water conditioning treatment to remove offensive tastes and odors, color, chlorine, volatile organic chemicals, pesticides, radon, and trihalomethanes. Activated carbon will not remove bacteria such as coliforms; dissolved metals such as iron, lead, manganese, and copper; or chlorides, nitrates, and fluorides.
Activated carbon filters, usually made up of granulated, powdered, or block carbon, act like a sponge with a large surface area to absorb contaminants in the water. Activated carbon, made from coal and nutshells, has a tremendous surface area -- as much as 125 acres per pound of carbon.
Home-use activated carbon filters are most commonly sold as faucet-mounted, stationary, and line bypass systems. The stationary system is connected directly to the cold water faucet. The line bypass system has a separate faucet, but is tapped into the cold water pipe for its water supply. These systems are typically installed under the sink and can be purchased for $50 to $375.
Activated alumina filtration. Activated alumina filters have one duty; to remove fluoride from water. But there is a tradeoff. Although an activated alumina filter lowers fluoride levels quite well -- and arsenic levels, too -- it adds a little bit of aluminum to the water. Some studies suggest that aluminum may contribute to the onset of Alzheimer's disease or exacerbate it.
Oxidation filtration. Oxidizing filters are used mainly for the removal of iron, manganese, and hydrogen sulfide. A manganese greensand filter provides oxygen to the iron and manganese in solution. As a result, these minerals change from their soluble to their insoluble forms. The "precipitated" minerals become trapped as rust particles within the greensand filter bed. To remain effective, manganese greensand filters must be periodically backwashed to thoroughly remove iron precipitates and regenerated when the oxygen is depleted.
Neutralizing filtration. Neutralizing filters are typically used for pH modification, that is, treating acidic water. A neutralizing filter is normally a pressure filter tank filled with limestone chips. As the water passes through the filter bed, calcium carbonate dissolves into the water, increasing its pH and reducing its acidity.
Reverse osmosis filtration. Reverse osmosis or R.O. filtration systems for home water conditioning are relatively new, although the process has been used extensively for industrial processes. Reverse osmosis water conditioning decreases the levels of dissolved minerals in the water.
It successfully treats water with a high salt content and with dissolved minerals such as nitrate sulfate, calcium, magnesium, potassium, manganese, aluminum, fluoride, silica, boron, and bicarbonate. R.O. is also effective with some taste-, color-, and odor-producing chemicals, certain organic contaminants, and some pesticides.
For additional information on water conditioning, obtain a copy of a new
University of Idaho Extension publication "Treating and Conditioning Home Water
Supplies" (Current Information Series No. 1001). This new publication can
be obtained free of charge from your local county Extension office.
PESTICIDE BMPs FOR YOUR LAWN
Your lawn is something you should be proud of! It is an attractive part of your landscape. In fact, a well-maintained lawn adds value to your property. Your lawn helps to tie your home and landscaping together.
A healthy, good looking lawn actually helps improve your living environment. On a hot day your lawn reduces the glare of the sun. Your lawn can also help keep surrounding areas cooler. A well-maintained lawn is much more attractive than pavement! Your lawn will attract birds and other wildlife. On windy days your lawn will trap dust particles from the air. And most importantly your lawn protects the soil on your property from erosion.
Inputs such as pesticides, fertilizers, and water when used incorrectly may adversely impact surface and/or groundwater quality. To protect the environment and water quality you should use Best Management Practices (BMPs), which are defined as implemented strategies that eliminate or minimize environmental pollution. BMPs are designed to be compatible with good, sound lawn management. BMPs can protect the environment without compromising the beauty of your lawn.
Why should homeowners be concerned about pesticides use on lawns
IFB WELLHEAD SURVEY:
JEFFERSON, MADISON, AND TETON COUNTIES
On October 28, 1993, Jefferson, Madison, and Teton counties became the 16th, 17th, and 18th counties in Idaho to take part in the wellhead survey program coordinated by the Idaho Farm Bureau Federation (IFB). Although this program was coordinated by the IFB it was truly a cooperative effort as five different government agencies and the Idaho Farm Bureau Federation united to make the program a success. The Idaho Department of Agriculture (IDA), Soil Conservation Service (SCS), Health District 7, and the University of Idaho Cooperative Extension System (UI-CES) assisted with program logistics, sample bottle distribution, and dissemination of information. The University of Idaho College of Agriculture's Analytical Laboratory (UI-AL) had major roles in planning and designing the quality assurance phase of the analytical part of the program and analyzed all samples for nitrates. The Idaho Division of Environmental Quality (DEQ) designed the quality assurance plan for the field effort, the questionnaire, and sampling procedures for the public. The United States Geological Survey (USGS) also participated in this study.
Quality control in this sampling project was the top priority. Blind spiked samples and blanks were randomly dispersed with farmer-provided samples to assure top quality. A total of 68 quality control samples were included in this study. In addition, in some cases, duplicate farm wellhead samples were included. Nitrates were determined on water samples by the UI-AL in Moscow. After collection, a preservative was added to the sample before shipment to Moscow. Samples were run in the laboratory within 72 hours after collection. The most modern analytical techniques and equipment were used in this operation. A high degree of confidence should be placed on the numbers obtained from these samples.
In the three counties, 212 private wellhead samples were collected from farmers and rural residents. Only one percent of the sampled wells in the three-county area contained nitrate-N levels greater than 10 ppm, which is the National Public Health Service drinking water standard. Thirty-five percent of the wells had nitrate-N levels above 2.0 ppm; 27 percent contained nitrate-N values between 2.0 and 4.9 ppm; and 8 percent of the wells had values of 5.0 ppm or greater.
The survey data can be broken down to evaluate each individual county. A total of 96, 83, and 33 wells were sampled in Jefferson, Madison, and Teton counties, respectively. All wells met the drinking water standards in Jefferson and Teton counties. Conversely, only one well exceeded the drinking water standard in Madison County.
LAND ZONING TECHNIQUES TO PROTECT GROUNDWATER
(This is the second in a series of articles on protecting groundwater quality by managing local land use.)
Since over 90 percent of Idahoans obtain their drinking water from groundwater it makes sense to consider different options to protect this resource. One option for county and city governments to consider is land use planning.
In most areas local land use activities can influence groundwater quality greatly. This close relationship between land use and groundwater quality means that local government, in exercising the traditionally local function of managing land use, can play a significant role in protecting this resource.
Measures to require that new land uses protect groundwater quality can include conventional zoning, flexible zoning devices, subdivision regulation, and extraterritorial controls.
Conventional zoning techniques. Zoning first developed in an urban context where its traditional purposes were to prevent conflicts between incompatible land uses and to limit overcrowding. In subsequent years, zoning has taken on an environmental focus through the regulation of "sensitive" lands such as shorelands, floodplains, wetlands, and, most recently, groundwater protection areas.
Zoning provisions establish use districts where specific uses are permitted as a matter of right, while other uses are either conditionally permitted or prohibited altogether. Zoning can provide flexibility in controlling land use. One example of such flexibility is designating conditional uses of special exceptions to help determine whether a particular use is appropriate to a specific site. Another example is adding overlay zoning to a conventional zoning ordinance.
Zoning authority also may be used to enact density provisions that govern the dimensions of lots, the dimensions of structures, and the location of structures on the lot. The basic purposes of these dimensional provisions are to control density and provide open space. Regulating the density of development indirectly controls the amount of potential pollutants reaching the groundwater, since maintaining open space with natural vegetation can improve the amount and quality of infiltration into the groundwater.
Flexible zone devices. Both conditional uses and overlay zoning are
flexible zoning devices.
Conditional uses. Conditional uses are devices that allow individualized treatment of certain uses according to the terms spelled out in the zoning ordinance. Permitted uses are automatically allowed if they meet the dimensional standards of the zoning district.
Conditional uses, however, are not allowed as a matter of right because they may
create special problems or hazards. Instead, a public hearing is held and a
determination is made on such concerns as the following:
The use of overlay districts provides protection to several types of special management areas. These include vulnerable areas, aquifer recharge areas, areas of suspected contamination, and well protection areas. The type of overlay district selected will depend upon the problems present and the information available. "Vulnerable areas" are areas in which contaminants can enter groundwater easily, such as areas of shallow soil over fractured bedrock, high water table soils, and excessively well-drained soils. In areas of suspected contamination, such as locations downflow from landfill sites, such special precautions as requiring that subdivisions be served by a single deep well rather than individual shallow wells can ensure a safe water supply. Areas recharging existing and future municipal wells or clusters of private wells, called "wellhead protection areas," may also be delineated and regulated. Flexibility is added by making many of the uses in overlay zones conditional uses, thus taking into account their likely impact on groundwater.
Subdivision regulations. Subdivision regulations focus on dividing larger tracts of land into lots for the purpose of sale or building development to promote public health, safety, and general welfare. Groundwater protection provisions are clearly within the scope of statutes authorizing local government to adopt subdivision regulations. Although traditionally directed at residential development, local subdivision ordinances can apply to commercial and industrial development. Subdivision plats are typically reviewed to ensure the physical suitability of the area, sufficiency of water supply and waste disposal systems, proper stormwater management, erosion and sedimentation control, adequacy of the street system, open space needs, and proper dimensions and layout of lots.
Local government can also impose additional conditions related to groundwater protection. For example, local regulations can require that a sub-divider provide monitoring wells and centralized sewer and water systems rather than individual systems.
Extraterritorial controls. The source of an incorporated
municipality's groundwater may be outside the locality's boundaries. This
situation may be addressed by statutes in some states that authorize cities and
villages to adopt extraterritorial subdivision and extraterritorial zoning
regulations to control land use beyond municipal boundaries. Extraterritorial
controls are best instituted as a part of a coordinated planning and regulatory
effort involving affected rural governments and incorporated municipalities.
(Adapted from Groundwater and Public Policy, Series No. 6 by D. A. Yaggen and S. M. Born from the University of Wisconsin-Madison)
IDAHO -- 2000!
We Idahoans use over 23,000,000,000 gallons of water each and every day. About 97 percent of this water is used in irrigated agriculture. The other 3 percent is consumed by industry, business, and in our homes.
Idaho is changing fast! Whether we like it or not, our state is growing rapidly. This growth is most apparent in the Boise, Coeur d'Alene, and Idaho Falls areas. It is likely that Idaho's population will top 1,200,000 by the year 2000. That's a population increase of at least 15 percent over the 1990 level of 1,060,000. If the state's economy continues at the levels seen in 1992 and 1993 our population could approach 1,350,000 by the year 2000 (a 27 percent increase over 1990).
The projected population increase will further tax our already limited water
resources. Increased demands for water will likely come from the following
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All contents copyright © 1997-2003. College of Agricultural and Life Sciences, University of Idaho. All rights reserved. Revised: January 3, 2003