BP BHEAD INT H [Atlas:Generic]

AN ACT Relating to the hydraulic continuity of ground and surface waters; and adding new sections to chapter 90.44 RCW.

BE IT ENACTED BY THE LEGISLATURE OF THE STATE OF WASHINGTON:

NEW SECTION. Sec. 1. A new section is added to chapter 90.44 RCW to read as follows:

For the purposes of this section and section 2 of this act:

(1) "Confined aquifer" means an aquifer in which ground water is under sufficient hydrostatic head to rise above the bottom of the overlying confining bed.

(2) "Confining bed" means a layer of low permeability material immediately overlying a confined aquifer.

(3) "Department" means the department of ecology or its successor.

(4) "Director" means the director of ecology.

(5) "Hydraulic continuity" means a connection between the water in a body of water located on the surface of land and water located in a subsurface aquifer as determined under section 2 of this act.

(6) "Unconfined aquifer" means an aquifer in which the hydrostatic head at the upper surface of the ground water is atmospheric.

NEW SECTION. Sec. 2. A new section is added to chapter 90.44 RCW to read as follows:

(1) The hydraulic continuity of ground water with a particular body of surface water shall be determined as provided by this section.

(a) If the ground water is in a confined aquifer, it shall be presumed that the ground water is not hydraulically continuous with the surface water body. The burden of proof in overcoming this presumption lies with a party, including but not limited to the department, asserting that the water in the aquifer is hydraulically continuous with the surface water body. A determination that water in a confined aquifer is hydraulically continuous with a surface water body must be based on a clear and direct connection between the surface water body and the ground water in the aquifer. The connection must be demonstrable through a reasonable and repeatable test or tests that can be applied in the field and that apply generally accepted methods of hydrogeologic science. With regard to water in a particular well, the information from the field tests shall be provided in water well reports for the well. If there is no water well report available for the well or if the information provided in such a report is inadequate for such a purpose, an assertion that the connection is demonstrable may be based on other information.

(b) It shall be presumed that water from an unconfined aquifer at a well or proposed well site that is located a horizontal distance of less than one-fourth mile from the nearest edge of a surface water body is hydraulically continuous with the surface water body. The burden of proof in overcoming this presumption is on a party, including but not limited to the department, asserting otherwise.

(2) All wells that produce water from an aquifer that is determined by field evidence to be hydraulically continuous to a surface water body shall be presumed to have the potential to cause substantial interference with the surface water body if the existing or proposed ground water appropriation is within one of the following categories:

(a) The point of appropriation is a horizontal distance less than one-fourth mile from the surface water source;

(b) The point of appropriation is a horizontal distance less than one mile from the surface water body and the rate of appropriation is greater than five cubic feet per second;

(c) The point of appropriation is a horizontal distance less than one mile from the surface water body and the rate of appropriation is greater than one percent of the pertinent adopted minimum instream flow or instream water right with a senior priority date, if one is applicable; or

(d) The point of appropriation is a horizontal distance less than one mile from the surface water body and the ground water appropriation, if continued for a period of thirty days, would result in stream depletion greater than twenty-five percent of the rate of appropriation. Using the best available information, stream depletion shall be determined or estimated employing at least one of the following methods:

(i) Suitable equations and graphical techniques that are described in pertinent publications, such as "Computation of Rate and Volume of Stream Depletion by Wells," by C.T. Jenkins, in: "Techniques of Water-Resources Investigations of the United States Geological Survey: Book 4, Chapter D1"; or

(ii) A computer program or ground water model that is based on such or similar equations or techniques.

The burden of proof in overcoming the presumption provided by this subsection (2) is on a party, including but not limited to the department, asserting otherwise.

(3) Any wells, other than those covered in subsection (2) of this section, that produce water from an aquifer that is determined to be hydraulically continuous to the surface water body may be determined to cause substantial interference with the surface water body. In making this determination, at least the following factors shall be considered:

(a) A demonstrable reduction in stream flow or surface water supply;

(b) A demonstrable impairment or detrimental effect on a surface water appropriation, adopted minimum instream flow, or instream water right with a senior priority date;

(d) There is interference and such interference would be immediate or delayed; and

(e) Demonstrable cumulative adverse impacts on stream flow or surface water supply.

(4) It shall be presumed that a well that produces water from an aquifer that is not hydraulically continuous to a surface water body does not interfere with the surface water body. The burden of proof in overcoming this presumption lies with a party, including but not limited to the department, asserting otherwise.

(5) The department shall provide reasonable assistance to an applicant or appropriator in securing available information pertinent to making a determination regarding hydraulic continuity and interference with a surface water body.