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disinfection can be accomplished as described for a
effectively sealed for safety and to prevent pollution of
water table well.
the ground water resources in the area. The
abandonment of wells shall follow the guidance of
5-8. Renovation of Existing Wells AWWA A100 and state/local regulations. Figure 5-6
Well yield can be maintained by proper operating
procedures. The most common cause of dedining
capacity in a well is incrustation which results from
material being deposited on the well screen and thereby
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illustrates the configuration of a gravel-packed well in operational condition and figure 5-8 illustrates well after
sealing.
Figure 5-8. Sealed well.
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5-10. Check list for design bacteriological analyses of water from existing wells.
a. Topographic maps of area where wells could e. Assessment of probable treatment
be located. requirements, such as iron-manganese removal,
b. Reports on area geology and ground water softening, corrosion control, sulfide removal.
resources from U.S. Geological Survey, State f. Summary of sanitary survey findings,
Geological Survey, and other state and local agencies including identification of possible sources of pollution.
that have an interest in or have conducted ground water g. Probable location, number, type, depth,
investigations. Records obtained from drilling diameter and spacing of proposed water supply wells.
contractors familiar with the area. Reports of test drilling Significant problems associated with well operation.
and pumping. h. Energy requirement of proposed system.
c. Copies of logs of existing water supply wells, i. Summary of applicable State water laws,
drawdown data, pumpage, water table elevations. rules, regulations, and procedures necessary to establish
Estimates of safe yield of aquifers. water use rights. Impact of proposed use on established
d. Records of physical, chemical and rights of others.
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CHAPTER 6
SURFACE WATER SUPPLIES
6-1. Surface water sources geographically and seasonally. Streams, in particular,
Surface water supply sources include streams, lakes, often exhibit fairly wide seasonal fluctuations in mineral
and impounding reservoirs. Large supplies of surface quality, principally as a result of variations in stream flow.
water are generally available throughout much of the In general, streams and lakes east of the 95th meridian,
eastern half of the United States where rainfall averages which includes most of Minnesota, Iowa, Missouri,
about 35 inches or more annually and is reasonably well Arkansas, Louisiana, and States east thereof, exhibit
distributed through the year. On the other hand, good dissolved mineral solids in the range of 100 or less to
surface water sources are much more limited in many about 700 milligrams per liter (mg/l). The water from
western regions with the exception of the Pacific these sources, after conventional treatment in a well-
Northwest, where surface water is plentiful. designed filtration plant, will meet standards prescribed
for potable water (see appendix A of TM 5-8133/ AFM
88-10, Vol. 3, for these standards). Unusual local
6-2. Water laws
conditions; e.g., pollution, may render some eastern
Any investigation directed toward development of new or
waters unsuitable as a source of supply; but in general,
additional sources of supply must include consideration
eastern streams and lakes are a satisfactory raw water
of applicable State water laws. Most of the States in
source. Similar comments are applicable to surface
roughly the eastern half of the United States follow the
waters of the Pacific Northwest area. Streams in many
riparian law of water rights, and only a few have permit
other areas west of the 95th meridian are much less
systems. Under this doctrine, the right to use water is
satisfactory, often showing dissolved mineral solids in the
associated with ownership of the land through which the
range of 700 to 1,800 mg/l. High concentrations of
stream flows. The riparian rights doctrine is essentially a
hardness-producing and other minerals such as sulfate
legal principle which may be used, in some form, to
and chloride are found in some western surface waters.
settle disputes. It does not automatically provide for
State water management and record keeping. Planning
for water supply systems under the riparian doctrine is 6-4. Watershed control and surveillance
not absolutely certain for present and future water Raw water supplies should be of the best practicable
availability and security. In contrast, western law is quality even though extensive treatment, including
based largely on the doctrine of "prior appropriation." In filtration, is provided. Strict watershed control is usually
the 17 Western States where this doctrine prevails, impractical in the case of water supplies obtained from
sophisticated legal, administrative and management streams. However, some measure of control can be
machinery exists. In these States, water rights and land exercised over adverse influences, such as wastewater
ownership are separable and most Western States discharges, in the vicinity of the water supply intake. For
authorize a water-right owner to sell the right to another. supplies derived from impounding reservoirs, it is
The new owner is permitted to transfer the water to generally feasible to establish and maintain a control and
another point of use or put it to a different use, provided surveillance program whose objective is protection of the
the transfer conforms to the State s administrative quality of raw water obtained from the reservoir. At
requirements. reservoirs whose sole purpose is to provide a source of
water supply, recreational use of the reservoir and
shoreline areas should be rigorously controlled to protect
6-3. Quality of surface waters
the water supply quality.
The quality of stream and lake waters varies
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*TM 5-813-1/AFM-88-10, Vol. 1
6-5. Checklist for surface water investigations f. Feasibility of developing supply without
The investigations will cover the following items, as well reservoir construction. [ Pobierz całość w formacie PDF ]