The purpose of this chapter is to establish and set forth the policies and procedures of the department of ecology in regard to the protection of the availability of groundwater as it pertains to the water withdrawal facilities of holders of groundwater rights.

This chapter is promulgated by the department of ecology pursuant to chapters 43.21A, 90.44, 90.54 and 18.104 RCW.

For the purposes of this chapter the following definitions shall apply:

(1) "Department" means the Washington state department of ecology.

(2) "Groundwater right" means an authorization to use groundwater established pursuant to chapter 90.44 RCW, state common or statutory law existing prior to the enactment of chapter 90.44 RCW, or federal law.

(3) "Withdrawal facilities" means and includes any well, infiltration trench or other excavation that is drilled, cored, bored, washed, driven, dug, jetted or otherwise constructed, together with the casing, screen, pump, pump column, motor and related equipment, which is used for the withdrawal of groundwater.

(4) "Aquifer" means any geologic formation that will yield water to a well or other withdrawal works in sufficient quantity for beneficial use.

(5) "Groundwater" means all waters that exist beneath the land surface or beneath the bed of any stream, lake or reservoir, or other body of surface water, whatever may be the geological formation or structure in which such water stands or flows, percolates or otherwise moves.

(6) "Contamination" means an impairment of the beneficial use of groundwater arising from the modification of the quality thereof by the introduction of organisms, chemical, organic or radioactive material or of heated or cooled water.

(7) "Significant modification" means the deepening or reaming of a well, lowering the pump bowls by adding lengths of pump column, adding water quality treatment devices, or other similar modifications, where the total cost or value of such modifications exceeds (1) $500.00 for domestic, stock or other water withdrawal facilities withdrawing less than 5,000 gallons per day, or (2) $2500.00 for all other facilities.

(8) "Qualifying withdrawal facilities" means those withdrawal facilities which in the opinion of the department constitute a reasonable development of the aquifer. A reasonable development must satisfy the following requirements:

(a) The withdrawal facilities must be constructed in accordance with chapter 18.104 RCW (Water Well Construction Act) and chapter 173-160 WAC (Minimum standards for construction and maintenance of water wells) and the water right permit provisions, if any, or the applicable state laws and the regulations of the department which were in effect at the time of construction of the facilities.

(b) The withdrawal facilities must have a depth of aquifer penetration which will allow the withdrawal of water from a reasonable or feasible pumping lift;

(c) The withdrawal facilities must be able to accommodate a reasonable variation in seasonal pumping water levels;

(d) The withdrawal facilities, including the pumping facilities, must be properly sized to the ability of the aquifer to produce water.

For the purposes of this chapter, reasonable or feasible pumping lift shall be determined by the department taking into account the following factors, among others:

(1) The geohydraulic characteristics of the aquifer;

(2) The state of construction technology of water withdrawal facilities;

(3) Historic considerations in regards to the construction, maintenance and use of water withdrawal facilities within the vicinity;

(4) The groundwater area or subarea management program for the vicinity, if one exists.

If the department determines that a proposed appropriation of groundwater would cause a lowering of the water levels below a reasonable or feasible pumping lift in any withdrawal facilities of an existing groundwater right holder or that approval of the proposed appropriation would impair any existing water rights or would otherwise be detrimental to the public welfare, the application shall be rejected. If, however, the application is to be rejected because of conflict with existing rights, and the applicant thereafter indicates that such existing rights will be acquired by the applicant by purchase, gift or condemnation under RCW 90.03.040, the department may issue an interim conditional ruling and defer final decision on the application for a reasonable period of time to be specified by the department in the interim ruling.

For the purposes of this chapter, a groundwater right which pertains to qualifying withdrawal facilities, shall be deemed to be impaired whenever:

(1) There is an interruption or an interference in the availability of water to said facilities, or a contamination of such water, caused by the withdrawal of groundwater by a junior water right holder or holders; and

(2) Significant modification is required to be made to said facilities in order to allow the senior groundwater right to be exercised.

Any senior groundwater right holder who believes that his water right has been impaired may notify the department of such impairment and request the assistance of the department to protect the availability of water to his qualifying withdrawal facilities. Such notification and request for assistance must be in writing and must contain the following information:

(1) Name, address and signature of the senior water right holder;

(2) Description of the water right, including the water right number if one exists; the quantities of water permitted and the quantities of water historically withdrawn; the priority date of the water right; the location of the withdrawal facilities; a description of the withdrawal facilities including well depth, casing, pump size and depth and historic water levels, and any recent changes made to the withdrawal facilities or the use of such facilities, especially in relation to WAC 173-150-030(8); the name of the water well contractor and a copy of the water well report of the construction of the withdrawal facilities, if available;

(3) Description of the alleged impairment of the senior water right, the date of the beginning of impairment, the degree of impairment and any steps taken by the senior water right holder to alleviate the impairment;

(4) Location and description of the junior water withdrawal facilities together with the name of the user thereof, if known, which in the opinion of the senior water right holder are the cause of the impairment;

(5) Any other pertinent information which may reasonably be required by the department.

Upon notification to the department of the impairment of a groundwater right as provided in WAC 173-150-070 or on the department's own motion, the department may, when appropriate, notify the water right holders of the alleged impairment and of its intention to make investigations concerning the matter. The department may conduct aquifer or pump tests and make investigations of the withdrawal works, geology, hydrology, water quality, historic water use or other factors which may influence the local aquifers, and may make a written report of its findings. If it is determined that groundwater withdrawals by a junior water right holder or holders have caused the impairment, the department may, through regulatory orders, take one or more of the following actions:

(1) Bar or regulate the withdrawals of the junior appropriator(s) in a fashion which will preclude future impairment of the senior right;

(2) Bar or regulate the groundwater withdrawals of the most junior water right holders in order of priority of right if the aggregate withdrawals exceed the maximum amount set by the department for the area, subarea or zone pursuant to the procedures of RCW 90.44.180;

(3) Require the well owner(s), including the senior water right holder, to rehabilitate or abandon the well(s) in accordance with chapter 173-160 WAC in the case of impairment caused by the failure of wells to meet the well construction standards or the requirements of water right permit or certificate provisions, if any;

(4) Rescind authorizations for additional junior withdrawal facilities and/or reduce the authorized withdrawal rates, as appropriate, where the department finds that an appropriation by a junior right holder is the cause of the impairment and where the said junior groundwater right holder has not yet completed construction of the authorized withdrawal facilities. The department shall include a provision concerning the possibility of such rescissions as a condition on groundwater permits with multiple points of withdrawal.

(1) Notwithstanding the provisions of WAC 173-150-080, should the senior and junior water right holders reach a voluntary agreement which satisfies the concerns stated in the notification of impairment, the department, if it determines that the public interest is fully protected thereby, shall not regulate the withdrawals by the junior water right holder under this regulation.

(2) If such an agreement includes provisions for the delivery of water from another water withdrawal facility to the holder of the senior water right, said agreement shall not take effect until all requirements of RCW 90.44.100 are satisfied or, if a new right to withdraw water is required to be established, a permit is issued pursuant to RCW 90.44.050.

As a general rule, an element of a groundwater right is the right to use waters of quality appropriate to the beneficial use. In addition to the protection of the availability of groundwater to the water withdrawal facilities of groundwater right holders, it shall be the policy of the department to protect the quality of the groundwaters of the state and in relation thereto to discourage any withdrawal facilities construction methods, water use or disposal practices which would contaminate or otherwise reduce the quality of the groundwaters or impair the beneficial uses of groundwaters of the state.

In addition to the procedures outlined in WAC 173-150-080, the department may regulate or control saltwater intrusion conditions caused by withdrawals from a freshwater aquifer or groundwater contamination caused by improper well construction techniques or other causes, through other means, including artificial recharge projects, the importation of additional water from other sources, or any other means deemed by the department to be reasonable, feasible and appropriate.

The provisions of this chapter shall apply to all groundwater rights and groundwater users under state jurisdiction, except that WAC 173-150-080 shall apply only to permits issued or other groundwater rights established subsequent to the effective date of this chapter, or to withdrawal facilities which are the subject of an application for change of water right filed pursuant to RCW 90.44.100 subsequent to the effective date of this chapter. Cases of impairment caused by facilities or groundwater rights which are not subject to this chapter shall be subject to existing state laws and regulations.

In enforcement of this chapter, the department of ecology may impose such sanctions as are appropriate under authorities vested in it, including but not limited to the issuance of regulatory orders under RCW 43.27A.190 and civil penalties under RCW 90.03.600.

All final written decisions of the department of ecology pertaining to permits, regulatory orders, and related decisions made pursuant to this chapter shall be subject to review by the pollution control hearings board in accordance with chapter 43.21B RCW.

The department of ecology shall initiate a review of the rules established in this chapter whenever new information, changing conditions, or statutory modifications make it necessary to consider revisions.

Nothing in this chapter shall be construed to in any manner limit the authority of the department to administer and enforce the existing water resources laws of the state, including but not limited to chapters 18.104, 90.03, 90.36, 90.44, 90.48 and 90.54 RCW, and regulations promulgated thereunder.