Nebraska Administrative Code › Topic - HEALTH AND HUMAN SERVICES SYSTEM › Title 179 - PUBLIC WATER SYSTEMS › Chapter 7 - SITING, DESIGN AND CONSTRUCTION OF PUBLIC WATER SYSTEMS › Section 179-7-007 - DESIGN STANDARDS

Current through June 17, 2024
007.01 The Director
				will review plans and specifications for substantial conformance to the
				"Recommended Standards for Water Works", 2007 Edition and the requirements of
				Title 179 NAC 7. In the event of discrepancy, Title 179 NAC 7 will govern. The
				Department will consider approving designs that follow generally accepted
				engineering guidelines and standards published by national engineering
				societies, federal environmental agencies, public health boards, engineering
				textbooks used by accredited university engineering programs, documented
				successful installations or successful pilot/full scale testing.
007.02 Chemical Feed Systems
All chemical feeders must have primary and secondary
				  interconnect control devices to prevent overfeeding. Where applicable, chemical
				  feeders must be electrically interconnected with the well or service pump and
				  must also be provided with secondary control devices as a means of reducing the
				  possibility of overfeed. An exception to this may be made for systems that have
				  warning devices and are staffed 24 hours a day, 7 days a week.
007.03 Wells/Groundwater Source(s)
1. Every well, infiltration line or spring
				serving or intended to provide water for a public water system, to the greatest
				extent possible, shall be located, constructed, or modified in such a manner
				that neither underground nor surface contamination by any biological, chemical
				or radioactive substance or by the physical property of any substance from any
				cesspool, privy, septic tank, sub-surface tile system, sewer, drain, pit below
				ground surface, abandoned or decommissioned well, animal or avian wastes, or
				any other possible source of pollution can adversely affect such water supply.
				The minimum recommended horizontal distances in feet separating the well,
				infiltration gallery or spring from potential sources of contamination are as
				described in the following table. The Department will consider location, of
				wells and springs at closer proximity than the minimum distances below.
				Approval for such location may be given when circumstances require such
				location, but only if, in the opinion of the Director, the engineer
				demonstrates that such location will not constitute a pollution hazard to the
				supply. The examples are not meant to be all inclusive. When locating a ground
				water source, the owner of a public water system shall consider all potential
				sources of contamination and anything which may affect the ability of the
				source to produce an adequate supply of safe water on a continuous basis. When
				surface runoff or underground movement from potential sources of contamination
				may adversely affect the quality of water from such supplies, the distance
				separating these potential sources of contamination and the well, infiltration
				gallery, or spring should be greater than that listed in the following
				schedule.
CATEGORY
DISTANCE Feet
Water Well
1,000
Sewage Lagoon
1,000
Land application of municipal/industrial waste
							 material
1,000
Feedlot or Feedlot Runoff
1,000
Underground disposal system (septic system, cesspool,
							 etc.)
500
Corral
500
Pit Toilet/Vault Toilet
500
Wastewater Holding Tanks
500
Sanitary Landfill/Dump
500
Chemical or Petroleum Product Storage
500
Sewage Treatment Plant
500
Sewage Wet Well
500
Sanitary Sewer Connection
100
Sanitary Sewer Manhole
100
Sanitary Sewer Line
50
NOTE: If the distance requirements in 179 NAC 13
				  Attachment 2 are not met, the well is subject to testing to determine if it is
				  ground water under the direct influence of surface water. If a well meets that
				  definition, it is treated as a surface water source subject to all the
				  requirements of the rules regarding surface water.
2. A test hole is required for all proposed
				well sites or the engineer must provide similar information that would have
				been provided by the test hole.
3.
				The annular space must be grouted (cement based grout) to a minimum depth of 10
				feet below the ground surface. If a pitless unit is to be installed, the upper
				limit of the cement based grout must be one foot below the field connection of
				the adapter. Crushed or chip bentonite must be installed from the top of the
				designed gravel pack to the base of the cement based grout. In order to
				accomplish this, the annular space must be 4 to 12 inches larger than the
				nominal casing size. Pouring into a dry annular space is preferred. Placement
				of the bentonite into the annular space must be done in a manner which ensures
				that bridging does not occur. Prior to using this material, it must be sieved
				over a 1/4 inch mesh screen to remove fines which may have accumulated in the
				bag during shipment. Any alternate annular space grouting/sealing proposed must
				be justified by the engineer with supporting documents.
4. The following information must be
				submitted with the plans and specifications, addenda thereto, or prior to
				construction:
a. Test hole driller's logs and
				reports or similar information.
b.
				All sieve analysis and calculations used in gravel pack and screen design. This
				information must be submitted prior to the placement of the screen and gravel
				pack.
5. The well casing
				must be at least two nominal sizes larger than the bowl size of the
				pump.
6. Well casing lengths must
				be joined by a watertight method appropriate to the material used so that the
				resulting joint will have the same structural integrity as the casing
				itself.
7. Cement-based grout must
				be placed by tremie pouring. The tremie pipe must be kept full continuously
				from the start to finish of the grouting procedure, with the discharge end of
				the tremie pipe being continuously submerged just below the surface of the
				grout until the zone to be grouted is completely filled.
8. The filter pack grain size must be
				determined by taking the 70% retained grain size of the finest formation to be
				filtered and multiplying it by 4, 5, or 6. This is the 70% retained grain size
				of the filter material to be used. The uniformity coefficient (the size of
				sieve that retains 40% of the sample divided by the size that retains 90%) must
				not be greater than 2.5. The gradation of the filter material must form a
				smooth and gradual size distribution curve when plotted. The screen aperture
				openings must be of such size as to retain between 85% and 100% of the filter
				material. The total open area of the screen must be such that the entrance
				velocity of water at the design condition does not exceed 0.1 feet per second
				(fps) with 50% of the screen open area blocked off.
9. The length of filter pack must extend a
				distance of 2-1 /2 times the maximum diameter of the well above the screen and
				below the screen, unless terminating in bedrock or clay.
10. The filter pack must be placed with a
				tremie pipe by washing or pumping the filter material in with water as a
				slurry.
11. The sand content must
				be determined from averaging the results of at least 5 samples collected over
				the course of the constant rate pump testing. The average of the sand content
				from these test results must not exceed two parts per million (ppm).