MANAGING IDAHO'S GROUNDWATER
Groundwater is a vital resource for most Idahoans. It becomes much more important during times of drought -- 1992! There are currently 13 areas in Idaho where water withdrawals are managed because of declining water tables.
Groundwater management within Idaho is governed under the Appropriation Doctrine. This system gives priority groundwater rights to the senior (oldest) wells. In times of shortage, withdrawals from the junior (newest) wells can theoretically be curtailed to provide water for the senior wells. Under this system, the Idaho Department of Water Resources (IDWR) issues permits for new wells on the basis of needs and impacts on existing water rights. The department considers anticipated rate of aquifer recharge and estimated groundwater pumping levels. The IDWR is the state's primary water administering agency.
A drop in the water table known as groundwater mining is a problem in some parts of Idaho. It occurs when water is withdrawn from an aquifer more rapidly than it is replenished. As the water table drops, water pumping costs increase. Eventually, the users run out of water.
Areas with extensive groundwater mining may experience reduced flows to surface waters and subsidence (lowering of the land surface). Reduced surface flows occur because groundwater springs are commonly a major source of stream flow during dry periods. Subsidence occurs when the removal of water leaves underground spaces that collapse or underlying clay strata shrink when dried.
Idaho has 13 areas where the IDWR manages aquifer withdrawals due to groundwater mining. These problem areas are termed either Groundwater Management Areas (GWMA) or Critical Groundwater Areas (CGWA). In 1988 Idaho listed five GWMAs (Boise Front, Mountain Home, Bruneau-Grand View, Banbury Hot Springs and Twin Falls). In these areas the IDWR must ensure that existing water rights in the area are unaffected by new construction.
More serious problems exist in eight CGWAs (Cinder Cone Butte, Blue Gulch, Artesian City, Cottonwood, West Oakley Fan, Oakley-Kenyon, Raft River and Curlew Valley) where groundwater levels are declining at a rate that threatens a reasonable safe supply for existing users. The IDWR issues no new well permits in these areas, and it limits groundwater withdrawals.
For example, the Cottonwood/Oakley Fan aquifer declines an average of about 5 feet per year and pumping lifts are 400 to 600 feet. Continued declines in this area will soon make groundwater pumping for agriculture economically unfeasible. Since aquifers can supply only a limited amount of water, farmers in the CGWAs will either have to increase water use efficiency or reduce irrigated acreage to maintain this groundwater resource.
PESTICIDES AND WATER
Water is an especially precious commodity in Idaho this year. It is always important to protect water from pesticide contamination, however it is more important when the water supply is short. Good common sense will help us get around the problems that may develop. How near is surface or groundwater? How much water is needed for pesticide application? Will the pesticide become attached to soil particles or will it move with the water?
Anything we grow -- yards, gardens, crops, and livestock -- may need pesticides for protection from attack of weeds, plant diseases, and insects. The technical and legal problems that may result from water contamination can only mean that prevention is the best answer. Water becomes contaminated due to the practices of pesticide users, presence of surface water at the application site, the chemical characteristics of the pesticide used, soil type of the site, and distance to the groundwater from the use site.
Before you use a pesticide read the label to find if it gives you any special precautions or steps to take to protect water. Avoid the temptation to use more than the label suggests not only because it is illegal, more costly to you and increases potential problems with the extra amount used. Consider the potential problems of the method you plan to use to apply the chemical. Chemigation, aerial application vs. ground application near a water storage or canal or soil injection with a high water table each present unique problems. Take precautions to prevent back-siphoning while filling your spray tank or chemigating. Locate your mixing and loading sites down hill from wells, ditches, and canals. When you do have your mixing and loading site near hazardous areas make a confinement area with a dike so if problems do occur, they will be minor. Dispose of your triple rinsed containers in accordance with local restrictions.
Some pesticides are much more apt to cause problems than others. Some
pesticides easily dissolve in water and will move wherever the water
goes. Others become attached to the soil and remain where they are
applied unless excessive irrigation or rainfall moves them into a wrong
area. Also, some pesticides last a lot longer in the environment than
others and move into the wrong areas over a long period of time until
they reach the groundwater. The label usually does not tell you the
above information, however it is available from the Cooperative
Extension Service or your SCS fieldman.
NON-POINT SOURCES OF WATER
Contamination sources are grouped as point or non-point sources. Point sources can be individually identified by point of release. Point source pollution of groundwater in Idaho is primarily from underground injection of waste, solid waste disposal sites (landfills), chemical spills, industrial chemicals, and underground fuel storage tanks.
Non-point sources are land uses that are numerous, dispersed, and usually individually insignificant in generating groundwater contaminants. It is the cumulative impact of these land uses when occurring in high densities that results in groundwater contamination. Common examples are septic tanks and agriculture. Most non-point source groundwater contamination can be grouped into three major areas: agriculture, septic systems, and urban runoff.
Many groundwater contamination problems in Idaho are under investigation or cleanup. The relative importance of non-point sources and point sources of groundwater contamination within Idaho is unknown.
Agriculture -- Contamination of groundwater from agricultural activities can occur in several ways. They include (1) mixing and handling fertilizers and pesticides; (2) disposing of excess fertilizers and pesticides after application; (3) cleaning equipment after application; and (4) applying fertilizers and pesticides under conditions that result in movement of water and chemicals through the soil to the aquifer (usually poor water management).
Responsible management of fertilizers and pesticides is essential to maintaining and improving Idaho's groundwater resource. Evidence shows that high levels of nitrates (more than 10 parts per million nitrate-nitrogen) can be harmful to infants and livestock. Recent studies, although not conclusive, suggest a link between long-term exposure to high levels of nitrates (more than 25 ppm) and stomach cancer. Pesticides in groundwater appear to be a much greater threat to human health than nitrates; however, measurement and assessment of pesticides are incomplete.
Using Best Management Practices (BMPs) is the primary step in protecting groundwater quality in the agricultural sector. BMPs protect groundwater by encouraging integrated crop management practices such as integrated pest management, efficient irrigation management, and soil sampling and testing for fertilizer recommendations. These practices minimize leaching of chemicals and help protect aquifer recharge areas and wells. BMPs are currently voluntary in Idaho, but they are often encouraged through government cost sharing programs and payments.
Farmers can protect their aquifers by following pesticide and fertilizer label directions and seeking professional advice on the application and handling of fertilizers, pesticides, and irrigation. Also, it is essential that all chemicals be safely stored on concrete pads away from wells. Agrichemical equipment should be rinsed far from wells or any areas sensitive to contamination.
Septic systems -- Approximately 58 percent of Idaho's residents rely on septic systems. Septic systems remove the solids from household sewage and discharge the fluid portion into the soil. If the system is properly designed and maintained, the soil then adsorbs or breaks down the pollutants.
More often, improperly designed or maintained septic systems leach contaminants into the groundwater. Currently, permits are required for septic tank installation, but post installation monitoring is rare, and most regulations do not control septic system density in vulnerable groundwater settings. In densely populated areas this can threaten groundwater.
Residents can help minimize groundwater problems by having septic systems checked, maintaining the system with frequent pumping and avoiding heavy use that can overload the system (for example, running several loads of laundry in one day).
Urban runoff -- The quality and quantity of urban runoff varies greatly depending on land uses, but the method of runoff management can determine whether groundwater becomes contaminated. Potentially harmful approaches include diverting untreated runoff into dry wells (shallow injection wells) or into unlined pits and basins. Contaminants found in urban runoff include nutrients, toxic metals, and oil and grease. In areas where salt is applied during snow removal, sodium and chloride may reach groundwater. Idaho has no comprehensive program to manage urban runoff, but local governments can modernize urban runoff systems to be more environmentally sound.
We can help decrease the toxicity of urban runoff by carefully handling all toxic materials. For example, garden fertilizers and pesticides should be applied according to label directions, and any excess should be stored carefully. They should never be emptied into a street gutter, poured down a drain, or set out with the weekly trash. Dispose of them at a certified hazardous waste disposal site or through a community household hazardous waste disposal.
Improper disposal of both empty and full chemical containers from urban, agricultural, and industrial sources has also caused groundwater contamination. These containers should never be discarded on land but should be taken to a hazardous waste disposal site unless otherwise specified on the label.
COMMUNITY WELLHEAD PROTECTION
As communities become more aware of both the potential health risks and the economic effects of groundwater contamination, they are beginning to look increasingly toward preventive efforts. The development of wellhead protection programs is a major preventive approach for the protection of community drinking water supplies.
If you live in a small community, chances are that groundwater is one of your town's most important and valuable resources. Chances are, too, that your community's water suppliers are concerned about doing whatever is necessary to protect the quality of your community's groundwater supplies.
The local government may or may not be directly responsible for a particular community's water supply. Nevertheless, once a water supply is contaminated, local officials do become involved in locating a clean supply, informing the public, and determining long-term solutions. Therefore, many communities across the country have taken the initiative to protect their water supplies by developing wellhead protection programs, which protect limited geographic areas around wells and wellfields that provide public water supplies. Established by the Safe Drinking Water Act of 1986, the Wellhead Protection Program is specifically designed to help states and local communities protect their public water supplies in ways appropriate to their unique situations.
Even when no immediate water-related concern appears to exist, a community should be concerned about protecting its drinking water supply for three reasons:
Avoiding the costs of cleanup and replacement of a water supply. Cleaning up contaminated groundwater can be technically difficult, extremely expensive -- and sometimes it simply cannot be done. Once a water supply is contaminated, replacement is often the most reasonable alternative, and the costs of siting new wells, treating existing supplies, or providing bottle water are high.
Preventing negative impacts. The negative economic effects of contaminated groundwater can extend far beyond the costs of remediation. Contaminated groundwater often discourages new businesses or residents from locating in a community. Existing businesses may be forced to move to an area with access to an uncontaminated water supply.
For all of these reasons -- health, remediation costs, and lost economic opportunities -- maintaining the quality of your community's groundwater is essential. The following outlines a five-step approach to developing a community wellhead protection program:
Step 1: Form a community planning team. It is critical to involve the broad interests of the community in this process, so that all viewpoints are considered in developing a local wellhead protection plan. These interests may include water suppliers; elected officials; local government agency representatives such as health, planning, and natural resources; businesses; developers; community service organizations; the farming community; environmental groups; and interested citizens. Regardless of the specific organization of the team, the basic goal is to provide for broad community participation in the planning process.
Step 2: Define the area that needs protection. By identifying the geographic area that contributes water to your well, you can limit the size of the area in need of the kind of special management and attention that will likely have an impact on daily operations of the community.
Your community may be able to obtain the kind of hydrologic information and expertise you need from county, state, or federal agencies, such as county Extension or Soil Conservation Service (SCS) offices, state health or environmental departments, or the U.S. Geological Survey. Another potential information source is local universities with departments in geology, water resources, agriculture, or civil or environmental engineering. Finally, you may know of citizens in the community who have professional expertise in these areas. The U.S. Environmental Protection Agency (EPA) can provide publications and a computer model for use in defining a wellhead protection area.
Step 3: Identify the problems that may contaminate your well. The process of identifying contamination problems should begin with a checklist of potential sources. Even though sources vary from community to community, a checklist is essential to assuring that a threat is not unintentionally missed in the identification process.
Checklists are available from your state groundwater office or EPA. A partial listing of sources to consider includes:
|gas stations||food processors|
|auto repair shops||pesticide usage|
|dry cleaners||junk yards|
|photo processors||heating oil storage|
|airports||domestic septic tanks|
|golf courses||auto washes|
|metal platers||boat refinishers|
Step 4: Begin special management of sources in the wellhead protection area. The next step is to begin managing the identified contamination sources -- both existing sources and new sources that may want to locate in the area. If the initial team selection process focused on those in the community who have the authority to implement management of identified sources -- including state and local officials who have the responsibility for education, planning, zoning, health, water supply, and other management activities -- then these team members would have agreed to the wellhead protection concept early in the process and can now provide the authority to direct the key implementation steps.
One of the most common ways to protect groundwater is to restrict certain activities within a certain distance from a well. Besides restricting activities within a wellhead protection area, a community can pursue other ways to protect groundwater. One option is to acquire high-risk areas for community-oriented land uses that have a low contamination potential, such as parks and recreation facilities. If this is not feasible, consider purchasing development rights to the land. Or reward landowners who do not conduct risky activities by easing their taxes. Another option is to prohibit outright the most threatening activities within critical areas.
Step 5: Plan for the future -- developing a contingency plan. Begin to develop a contingency plan in the event that your wells become contaminated despite your efforts. Even the most comprehensive and stringent wellhead protection program may fail to protect your wells.
A contingency plan should outline response procedures in the event of
water supply disruption due to contamination or any other reason. State
drinking water officials can identify both the individuals and
organizations to notify immediately after an accidental release, as
well as the types of equipment you would be likely to need in the event
of a contamination incident. If your community does not have the
recommended equipment, locate the nearest municipality that does.
(Adapted from Groundwater and Public Policy Series No. 13)
SMALL COMMUNITIES: OVERCOMING
OBSTACLES TO WELLHEAD PROTECTION
Small communities often have very limited resources for implementing wellhead protection programs. Recognizing this fact, there are a number of ways to stretch the resources that are available.
RESEARCH UPDATE: DETOXIFYING RESIDUES
IN USED CONTAINERS
Over 30 water quality research projects are being currently conducted by College of Agriculture faculty. One of these projects, which has produced some promising results, is the microbial detoxification of pesticide containers and rinseates. This project is under the direction of Dr. Ron Crawford in the Department of Bacteriology and Biochemistry. He is working in collaboration with Drs. Don Thill and Hugh Homan in the Department of Plant, Soil, and Entomological Sciences. This research was supported in part by Idaho tax dollars and by the United States Department of Agriculture (USDA).
The objective of this research and development project was to develop commercial preparations of immobilized microbial cells that could be used to destroy toxic residues of pesticides and carrier chemicals remaining in used chemical containers and/or agricultural industry rinse waters.
Wastes and residues from mixing, loading, and cleaning operations of pesticides present a difficult challenge for proper disposal to their users. Major problems concern the detoxification and disposal of empty containers, tank rinse waters, leftover materials, equipment wash waters, and spilled materials. Although triple-rinsing containers has been considered sufficient for cleaning under EPA guidelines, the process is hard to enforce, and some landfills refuse to accept used pesticide containers of any kind. A single washing of the outer surface of ground spray rigs and aircraft can produce 80 to 100 gallons of rinseate containing dirt, oil, hydraulic fluids, insect parts, and pesticides.
The best way to deal with the problem of hazardous pesticide residues is either to avoid generating them or to detoxify them directly at the point of production. This project was aimed at direct detoxification as a possible solution. Two graduate students have developed an inexpensive method for direct on-site detoxification of parathion and 2,4-dichlorophenoxyacetate (2,4-D) residues in used containers and/or agricultural rinse waters.
In this process, specific microbial cultures that degrade parathion or 2,4-D were immobilized by entrapment or adsorption on different polymer surfaces. Microbial cells known to be active degraders of parathion were trapped in alginate and freeze-dried. Alternatively, cell cultures were immobilized and air-dried on kaolinite clay. A microbial culture containing bacteria isolated for its ability to grow on 2,4-D was immobilized in alginate and freeze-dried with good survival rate for at least 90 days. Cells adsorbed to filter paper in the presence of skim milk also survived well. Both the parathion degraders and the 2,4-D degrader retained the ability to degrade their target compounds after extended storage. Both microbial preparations have been shown to degrade their target compounds in residues from used containers.
The ultimate goal of the project is to produce "packets" of microorganisms that could be attached to pesticide containers for treatment of empty containers, or packets that would be available separately for treating contaminated rinseates. The use of such microbial products would eliminate the hazardous residues at their source. Since fewer than 30 active ingredients make up 90 percent of the pesticides used annually in the U.S., a few successful applications of this technology could have a major national impact in reducing pollution by pesticide residues. The advantages in cost, safety, and simplicity would enable this technology to be widely adopted by users of agricultural chemicals nationwide.
At this point in the project, the parathion and 2,4-D model systems for testing under field conditions are being scaled up. Field testing will be done within the next year in cooperation with an agricultural chemical production company. The effectiveness of this biotreatment, storage life in the field, cost, and product acceptability by users are all phases being tested to estimate the commercial potential for these products. Two separate companies are in current negotiations for marketing. Home consumers, which are heavy users of 2,4-D products, are another possible market for this product. Additional funding from the Environmental Protection Agency (EPA) is currently being sought to continue this process for testing other agricultural pesticides and chemicals.
In summary, wastes and residues from the distribution and handling of agricultural chemicals are significant sources of environmental pollution. The goal of UI research is to destroy these potential environmental contaminants at their sources, such as in used containers and agricultural rinse waters. Immobilized microbial products that degrade parathion and 2,4-D residues have been successfully developed. Similar products can be produced for many other chemicals used in agriculture or industry. The commercialization of these immobilized cell products will significantly decrease non-point source water pollution by agricultural and industrial chemicals by destroying them before they could be leaked to the environment.
WATER CONSERVATION -- LOW-FLUSH
Low-flush toilets are becoming an increasingly popular way to reduce home water use. As a matter of fact, legislation mandating that only ultra low-flush toilets (1.6 gallons) be sold in New York State took effect in January, 1991. Most homes in the USA still have the seven gallons per flush (gpf) toilets, while others have the 3.5 gpf toilets that have been the standard for approximately ten years. Do ultra low-flush toilets really work?
To address this problem research sponsored by the American Society of Plumbing Engineers Research Foundation through the Stevens Institute of Technology is assessing the effectiveness of the 1.6 gallon (ultra low-flush) toilets in the laboratory. Field tests to assess performance in actual usage are currently underway. Twelve conventional (3 gpf) toilets, 12 gravity ultra low-flush (GULF) toilets, and two pressurized ultra low-flush (PULF) toilets were subjected to standard tests mandated by the American National Standards Institute (ANSI).
All toilets did well with no statistical differences on the waste removal tests that involved flushing of polypropylene balls, polyethylene granules, and latex cylinders. All but two models, one conventional and one GULF passed the dye test that determines the completeness with which the bowl water is replaced in a flush. All toilets did well when tested for ability to clean the bowl by flushing. All toilets also passed the carryout test that requires 100 polypropylene balls to be carried down a four inch drain at least 40 feet.
The real difference between conventional and low-flush toilets showed up in mixed media tests, which simulate non-homogeneous bulk wastes and are more representative of actual use. In these tests, three artificial sponges, three natural sponges, one latex cylinder, and two non-woven fabric wipes are placed in a bowl together. If any of the objects fails to clear the bowl or trapway, the trial is a failure. The PULF toilets performed perfectly, but the GULF toilets scored significantly lower than the conventional toilets. Another test with mixed media, the transport test, measures the sum of the distance that each object is carried down the drainline. Here the conventional toilets average difference was twice that of the GULF. The PULF results were intermediate.
Actual tests in the field will give further information. The
researchers feel that they are close to an optimum flush volume for
gravity-type water closets. Until that optimum is determined, it
appears that PULF toilets are the better choice. Most people buy the
1.6 GULF toilets because of price. When using these toilets, the amount
of paper used should be kept to a minimum or two flushes will be
required. Those still using 7.0 gallon toilets should be putting a
displacement device in the tank to cut the volume to between 3 and 4
gallons per flush.
(Source: TXA News 6-92)
THE SAFE DRINKING WATER
The Safe Drinking Water Act was passed by Congress in 1974, and has been amended several times since then. The Environmental Protection Agency (EPA) is the federal government agency which writes the regulations to carry out the provisions of the Act. The purpose of the Act is to make sure that the drinking water supplied to the public is safe and wholesome. EPA accomplishes this by setting national drinking water standards which all water supplied to the public must meet. The people who supply the water are responsible for making sure that the water meets the standards. It is important to note that the Safe Drinking Water Act does not provide funds for construction of water systems or ongoing operation and maintenance.
The Act was amended most recently in 1986. The amendments require the development of more drinking water standards and more technical requirements.
The federal drinking water program was designed to be delegated, which means that approved government agencies (usually states) carry out the program on a day-to-day basis. EPA provides guidance, technical assistance, and some financing to these agencies. Most states including Idaho have been delegated "primacy," or the authority to run the program. In the states and Indian lands which do not have primacy, EPA runs the program directly. The Idaho Department of Health and Welfare (IDHW) keeps track of sample results, conducts detailed inspections called sanitary surveys, and takes enforcement actions such as imposing fines and penalties when necessary. IDHW also provides technical assistance to owners and operators of public water systems.
The requirements of the Safe Drinking Water Act apply to all public water systems. A public water system is one which provides piped water to at least 25 people or 15 service connections for at least 60 days per year.
Public water systems are divided into two categories: community systems and noncommunity systems. A community system serves people year-round (a small town, for example), whereas a noncommunity system serves people only for a portion of the time (a hotel or campground, for example). Different requirements apply to each type of water system. Systems serving the same people day after day, such as institutions or factories, may be considered community water systems for purposes of the Act. These are called non-transient-noncommunity water systems.
The three major types of requirements in the Safe Drinking Water Act are: (1) sampling and reporting, (2) record keeping, and (3) public notification. A description of these follows. Keep in mind that the owner or operator of the water system is responsible for meeting these requirements.
Sampling and Reporting: Each supplier of water must collect samples from the water system, take them to an approved laboratory for analysis, and send the results to the regulatory agency (usually the state or county health department). The type of analysis performed, the sampling frequency, and the location of the sampling point vary from system to system, and chemical to chemical. Some states perform the sampling for the systems in their state.
Record Keeping: The laboratory results, name of person who collected the samples, dates and locations of sampling points, steps taken to correct problems, sanitary survey reports, and other information must be kept on file by the water supplier.
Public Notification: Any time there is a violation of a
two categories, Tier 1 and Tier 2, depending on the seriousness of the
violation. For example, a violation of a standard, indicating
contamination in the system, is more serious than a failure to meet a
compliance schedule imposed by the regulatory agency. Therefore, the
violation of the standard would be considered Tier 1, and more
extensive public notification would be required. The public notice must
meet certain minimum requirements concerning the way that they are
issued and their contents.
(Source: EPA, Region 9)
Streams are unique in their looks and functions, but all streams have physical and biological capabilities that provide them with the ability to support both human and wildlife resources. When a stream is outside an urban area, management of the riparian zone is less affected by human impact. That is to say, less people movement or traffic vs. animal or farming practices.
When a stream is surrounded by a dense urban area such as Boise, Spokane, or Idaho Falls, the stream's character usually changes. It still has the potential to be a wildlife corridor -- a greenbelt separator between neighborhoods or a wetland ecosystem with its own completeness. It can also be a center for recreation with an extremely high amount of use. However, riparian areas in these settings become increasingly difficult to manage, because of the high demands placed on them due to urbanization.
The stream's shape, materials, associated vegetation, and riparian landscape dictate how effective the corridor will be as a resource. For example, as a city develops, there becomes less soil surface area exposed to absorb water from rainfall, thereby increasing the potential for flooding and decreasing sediments going into the stream. When this occurs there is a greater chance for deep incision. This quickly changes the effectiveness of the stream and reduces the riparian vegetation. A stream can be landscaped to help reduce the velocity associated with high water flows.
A good example of urban streamside management is the Boise River as it flows through downtown Boise. Recently Hal Swenson, a soil scientist with the Soil Conservation Service stationed in Boise, and T. A. Tindall, UI extension soil specialist, evaluated the river from Park Center to Ann Morrison Park. This section of the river is heavily used and in some places "people traffic" is very intense. Trails have been incised into the steep banks for easier access to the water. These trails increase sediments into the river with the potential reduction of fish habitat. Although the affected areas are small, they might add up to be more serious if measures are not taken to reduce the bank erosion.
Although the Boise River is used throughout the year, there is a single event called the Boise River Festival which has the potential for significant negative impact on the stream and the associated riparian vegetation. Last year was the first for the festival. The response from the public was tremendous. An estimated 125,000 people watched or participated in the event. Crowds at times 10 people deep lined the steep banks along the south side of the river. This type of impact could seriously affect the riparian area if measures are not taken to lessen the impact. The area where the floats were put into the river was devoid of vegetation. Whether it was completely associated with the festival is not clear, but management considerations could be implemented to decrease this impact.
This is just one example of a riparian area which is heavily used in an urban Idaho setting. Recommendations for repairing other damaged areas of riparian zones might include the following:
MORE WATER FACTS
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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