Chapter 17.181
SENSITIVE GROUNDWATER OVERLAY ZONE
Sections:
17.181.010 Purpose.
17.181.020 Definitions.
17.181.030 Applicability.
17.181.040 Required review and application.
17.181.060 General provisions.
17.181.070 Study requirements.
17.181.100 Hydrogeology reviews.
17.181.110 Hydrogeology studies.
17.181.120 Water level monitoring.
17.181.130 Qualifications for performance of hydrogeology reviews and studies and well monitoring plans.
17.181.140 Conditions of approval for land uses relying on groundwater.
17.181.150 Review of hydrogeology studies.
17.181.160 Administration.
17.181.010 Purpose.
The purpose of this chapter is to implement the groundwater resources goals and policies of the environmental quality and natural resources section of the Marion County Comprehensive Plan. This chapter implements the program to review land use applications to assess the risk that a proposed use will adversely affect the sustainability of aquifer production. This chapter is not intended to act as a guarantee that a property owner will successfully locate an adequate water supply at a particular location or on a specific lot or parcel, or that any individual well will continue to provide adequate water for an existing land use. [Ord 1274 § 4, 2008; Ord. 1216 § 4, 2005; Ord. 1194 § 4, 2004; Ord. 1068 § 4, 1997. RZ Ord. § 181.010.]
17.181.020 Definitions.
The following definitions apply to this chapter only, and have no applicability to the same terms used in other chapters of this title, unless specifically stated:
A. “Aquifer” means a layer of rock or alluvial deposit which holds water.
B. “Development permit” means a county building or manufactured dwelling placement permit, including any land use decision, as defined in
ORS 197.015, required by this title to be made prior to issuance of the building or manufactured dwelling placement permit.
C. “Exempt-use well” means a well from which water use is exempt from permitting requirements of the Oregon Water Resources Commission. Water from such a well will be used only for the following purposes:
1. Stock watering;
2. Watering any lawn or noncommercial garden not exceeding one-half acre in area;
3. Single or group domestic purposes in an amount not exceeding 15,000 gallons a day;
4. Down-hole heat exchange purposes; or
5. Any single industrial or commercial purpose in an amount not exceeding 5,000 gallons a day.
D. “Groundwater” means any water, except capillary moisture, beneath the land surface or beneath the bed of any stream, lake, reservoir or other body of surface water, whatever may be the geological formation or structure in which such water stands, flows, percolates or otherwise moves.
E. “Permitted well” means a well from which the intended use of water requires a registration, certificate of registration, application for a permit, permit, certificate of completion or groundwater right certificate under ORS 537.505 through 537.795 and 537.992.
F. “SGO” means the sensitive groundwater overlay zone, as shown on the official Marion County zoning map. The SGO zone is comprised of two elements: the SGO zone and a number indicating the threshold lot size for that area (e.g., SGO-5).
G. “Well log” means a record of information about a new or altered well, as described in ORS 537.765. [Ord 1274 § 4, 2008; Ord. 1216 § 4, 2005; Ord. 1194 § 4, 2004; Ord. 1068 § 4, 1997. RZ Ord. § 181.020.]
17.181.030 Applicability.
A. The provisions of this chapter shall apply to all lands within the sensitive groundwater overlay zone boundary as shown on the official county zoning map. The overlay zone shall be applied to areas designated by the Oregon Water Resources Commission as groundwater limited areas and other parts of the county where information provided by a licensed geologist or through a county well-monitoring program indicates that a reasonable risk of over-appropriation of groundwater exists.
B. Nothing in this chapter shall be construed to constitute a waiver or suspension of the provisions of the underlying zone or other overlay zone. In the case of any conflict between the provisions of this chapter and any other provisions of this title, the more restrictive shall apply. [Ord 1274 § 4, 2008; Ord. 1216 § 4, 2005; Ord. 1194 § 4, 2004; Ord. 1068 § 4, 1997. RZ Ord. § 181.030.]
17.181.040 Required review and application.
All development permits for new land uses that rely on water from exempt-use wells within the sensitive groundwater overlay zone shall be reviewed by the county to determine compliance with this chapter.
The applicant for such a development permit shall submit the request on a form approved by the director along with a site plan of the subject property showing existing and proposed property boundaries; existing, abandoned, and proposed wells on the subject tract; and any other information as required in this chapter. The board may establish a fee for review of water-supply studies and well monitoring plans for new land uses. [Ord 1274 § 4, 2008. RZ Ord. § 181.040.]
17.181.060 General provisions.
Applicants for a development permit where the new land use will rely on groundwater in the sensitive groundwater overlay zone are subject to the following requirements:
A. Any wells on the tract subject to temporary or permanent abandonment under ORS 537.775 shall be abandoned prior to final development permit approval.
B. The well shall be made available to the county for monitoring purposes, pursuant to the county well-monitoring program ordinance.
C. Evidence that any required permits from the Oregon Health Division for use of the water have been obtained shall be submitted to the county prior to development permit approval, or final plat approval in the case of partitions, subdivisions, and planned unit developments. [Ord 1274 § 4, 2008; Ord. 1216 § 4, 2005; Ord. 1194 § 4, 2004; Ord. 1075 § 4, 1998; Ord. 1068 § 4, 1997. RZ Ord. § 181.060.]
17.181.070 Study requirements.
The following water-supply studies shall be required by the county to help determine whether a land use action will have an adverse impact on groundwater resources:
A. Residential Partitions, Planned Unit Developments, and Subdivisions. The following provisions apply to land divisions in the sensitive groundwater overlay zone, where the residences will utilize exempt-use wells:
1. Applications to partition a parcel of land shall be subject to the following requirements:
a. If the minimum parcel size proposed in the application is equal to or greater than five acres, no demonstration of water supply is required;
b. If the minimum parcel size proposed in the application is less than five acres, the application shall be accompanied by a hydrogeology review pursuant to MCC 17.181.100.
2. Within the SGO zone, applications to subdivide a parcel of land shall be subject to the following requirements:
a. If the minimum lot size proposed in the application is equal to or larger than five acres, no demonstration of water supply is required;
b. If the minimum lot size proposed in the application is less than five acres, the application shall be accompanied by a hydrogeology review pursuant to MCC 17.181.100;
c. An approved water level monitoring plan is required as a condition of approval for all subdivisions pursuant to MCC 17.181.120.
B. New Dwelling on an Existing Lot. When the application is for a development permit for a new dwelling that is reliant upon an exempt-use well on a lot existing on the effective date of the ordinance codified in this chapter, the requirements of this section apply:
1. Prior to approval of the building or manufactured dwelling placement permit, the owner shall be required to sign and allow the entering of the following declaratory statement into the chain of title for the subject parcel:
The property herein described is situated in a “Sensitive Groundwater Overlay” zone. The availability of groundwater may be limited, and if a long-term decline in water supply occurs the property owner may need to find an alternate source. Marion County is not responsible for deepening or replacing wells that fail to produce an adequate supply of groundwater.
2. Subsection (B)(1) of this section does not apply to dwellings on lots or parcels within:
a. A partition that was subject to application under the provisions of this chapter; or
b. A subdivision approved by the county after October 1, 1992. [Ord 1274 § 4, 2008; Ord. 1216 § 4, 2005; Ord. 1194 § 4, 2004; Ord. 1068 § 4, 1997. RZ Ord. § 181.070.]
17.181.100 Hydrogeology reviews.
The purposes of a hydrogeology review are to provide information regarding the geology and hydrogeology of the area in the immediate vicinity of the proposed development and to furnish professional analysis of the information. A hydrogeology review generally requires compilation and analysis of existing information but not development of new data. Study findings, maps, and conclusions shall be presented in a clear and understandable report.
A. A hydrogeology review report shall include, at a minimum, the following information:
1. A map showing all lots and parcels within at least one-quarter mile of the proposed development;
2. The location of all wells within at least one-quarter mile of the proposed development, and the quantity of water permitted to be used;
3. The estimated use of groundwater within at least one-quarter mile of the proposed development, including 525 gallons/day use for each lot and parcel and water use from permitted wells (as required in subsection (A)(2) of this section);
4. The quantity of water the proposed land use will utilize. If the proposal is for residential use, water use shall be calculated as 525 gallons/day. If the proposal is for a land division for residential purposes, all proposed lots or parcels shall be included in the calculation;
5. Identification of aquifers in the area of the subject property;
6. Compilation and review of available geologic and hydrogeologic studies of the area;
7. Compilation and evaluation of well deepening and replacement well information;
8. Compilation and analysis of existing geologic information, including representative well logs, physical location of representative wells, and an evaluation of the local stratigraphy and geologic structure;
9. Compilation and analysis of existing water level and pump test information including evaluation of long-term stability of groundwater levels (heads); and
10. Interpretation of the information gathered for subsections (A)(1) through (7) of this section, including preparation of geologic and hydrogeologic maps and cross-sections necessary to support and/or illustrate the interpretation.
B. A hydrogeology review shall demonstrate the following:
1. The available geologic and hydrogeologic information is sufficient to make a reasonably accurate estimate of the groundwater budget;
2. The geologic conditions that affect the recharge and discharge of groundwater;
3. The locations and causes of well deepenings and/or replacements in the area of concern;
4. Long-term water level (head) trends in the area of concern, if available; and
5. The groundwater budget for the area of concern indicates that additional recharge is available for the proposed new use. The groundwater budget will:
a. Assume that all lots and parcels in the area of concern are developed; and
b. Use the recharge data and assumptions contained in “Geologic and Hydrogeologic Study of the Residential Acreage-Zoned Areas of Marion County Underlain by the Columbia River Basalt and Older Rocks” (NGS, 1997) or explain why another source is used; and
c. Assume that one dwelling results in use of at least 525 gallons per day.
C. Hydrogeology Review Results. A hydrogeology study pursuant to MCC 17.181.110 shall be required if the hydrogeology review establishes that any of the following circumstances exist. If none of the following circumstances exist, no further evidence of water availability is required. As used in this section, “proposed development” includes any water conservation practices or standards proposed in the application that will influence the quantity of water needed for the use.
1. More than 90 percent of the recharge in the area of concern will be used after the proposed development is completed;
2. The proposed use will adversely affect the long-term water supply of existing uses or potential new uses on existing vacant parcels in the area of concern;
3. The additional proposed use will deplete the groundwater resource over the long or short term; and
4. Existing information is inadequate to determine whether any of the circumstances described in subsections (C)(1) through (3) of this section exist. [Ord 1274 § 4, 2008; Ord. 1216 § 4, 2005; Ord. 1194 § 4, 2004; Ord. 1068 § 4, 1997. RZ Ord. § 181.100.]
17.181.110 Hydrogeology studies.
The purpose of a hydrogeology study is to provide professional conclusions and recommendations regarding long-term aquifer capacity in areas where there is already considerable evidence that the groundwater resource is inadequate to support additional development. A hydrogeology study will include development of new data to help determine the availability of groundwater in the immediate vicinity of a proposed development. Study findings, maps, and conclusions shall be presented in a clear and understandable report.
A. A hydrogeology study report shall include, at a minimum, the following information:
1. The information required for a hydrogeology review in MCC 17.181.100(A);
2. Identification of aquifers in the area, characterization of aquifer properties, and estimation of the amount of use from each aquifer;
3. Estimation of a detailed groundwater budget for the proposed development and surrounding area;
4. Factual support for interpretations and study conclusions, which may include, but is not limited to: water level monitoring, pump tests to define aquifer properties, and surveys of well owners in the area; and
5. Identification and discussion of all assumptions and methods employed in the study together with a discussion of the uncertainties of the analysis and the probable size of errors inherent in the assumptions and methods employed.
B. The report shall include the following findings and recommendations in a form usable by the county in making a land use decision:
1. Identification of the level or density of development the aquifer(s) supplying the proposed development can sustain without exceeding 90 percent use of recharge;
2. Identification of specific measures that can be employed to mitigate impact of the proposed development on existing users of groundwater and the groundwater resource. [Ord 1274 § 4, 2008; Ord. 1216 § 4, 2005; Ord. 1194 § 4, 2004; Ord. 1068 § 4, 1997. RZ Ord. § 181.110.]
17.181.120 Water level monitoring.
The purpose of water level monitoring is to provide new data in areas where no or inadequate monitoring is currently being done to determine if current measures protect groundwater resources and enable the development of more accurate hydrogeology reviews and studies. Monitoring data, analysis, and conclusions shall be presented in a clear and understandable report in a format that is compatible with Oregon Water Resources data management systems to allow pooling of data.
A. Monitoring Requirements for Partitions in SGO Zones.
1. Static water level measurements shall be made in all existing wells prior to recording the plat.
2. For undeveloped lots created by partitions in SGO zones, at least one static water level measurement shall be made prior to the issuance of a building permit in any new or existing wells intended as the water supply for the lot. This requirement is only for lots created by partitions recorded after January 1, 1998.
3. For new wells, the measurement shall be made at least 72 hours after the well is completed. The static water level reported on the well log cannot be used to meet these requirements.
4. All measurements shall be reported on a form provided by the county.
5. A tax lot map showing the location and identification of each measured well shall accompany the form.
6. Each measurement shall be associated with all corresponding well log identification numbers and the Oregon Water Resources well tag number, if available.
7. Water levels shall be measured with an electric or steel tape or other suitable equipment on a list approved by the county.
8. Measurements shall be reported in decimal feet to at least the nearest 0.5 feet.
9. Measurements shall be made after the well has been idle for a minimum of eight hours, if practicable, or after the well has been idle at least the same length of time it was last pumped. The length of time the well was idle prior to the measurement shall be recorded and care shall be taken to determine and report whether the water level was static or still recovering from recent pumping.
10. All measurements shall be made by a registered geologist, licensed professional engineer, water well pump installer, certified water rights examiner, or by Marion County or Oregon Department of Water Resources staff.
B. Monitoring Requirements for Subdivisions in SGO Zones.
1. An approved water-level monitoring plan is required as a condition of approval for subdivisions.
2. The monitoring plan shall be submitted to the county for peer review and is subject to approval by the county.
3. The monitoring plan shall be approved and implemented before building permits are issued.
4. A minimum of one observation well per 15 lots is required in each subdivision and at least one observation well is required for each phase of a subdivision. Monitoring shall begin at the start of development of Phase 1 of an approved subdivision. A report that includes an analysis of data collected to date shall be submitted to the county for peer review prior to approval of the next phase of development.
5. Evidence of water level declines shall require preparation of a hydrogeology study prior to the release of the next phase for development if the county determines that the available data suggests that groundwater supplies may not be sufficient for additional development.
6. Access easements that allow county and OWRD personnel to measure water levels shall be recorded with deeds for lots containing an observation well as a condition of approval of the subdivision. [Ord 1274 § 4, 2008. RZ Ord. § 181.120.]
17.181.130 Qualifications for performance of hydrogeology reviews and studies and well monitoring plans.
In order for the county to accept a hydrogeology review, hydrogeology study, or well monitoring plan pursuant to MCC 17.181.100, 17.181.110, and 17.181.120, the report shall bear the stamp of a geologist, engineering geologist, or professional engineer that qualifies under ORS Chapter 672, registered with the state of Oregon. [Ord 1274 § 4, 2008; Ord. 1216 § 4, 2005; Ord. 1194 § 4, 2004; Ord. 1068 § 4, 1997. RZ Ord. § 181.130.]
17.181.140 Conditions of approval for land uses relying on groundwater.
Any conditions placed on the approval of a development permit resulting from information gathered pursuant to this chapter shall be designed to mitigate possible aquifer or well deficiencies identified by the results of the tests or studies required by this chapter. Such conditions shall be reasonable. Conditions may limit development and may include, but are not limited to, the following requirements:
A. Water storage;
B. Metering;
C. Well monitoring and water level reporting;
D. Phasing of development;
E. Conservation measures, such as designating the type and/or extent of landscaping and irrigation systems;
F. Minimum well spacing;
G. Water conservation planning;
H. Planning for remedial action (in conjunction with monitoring);
I. Well sharing; and
J. Placement of requirements as deed covenants/restrictions. [Ord 1274 § 4, 2008; Ord. 1216 § 4, 2005; Ord. 1194 § 4, 2004; Ord. 1068 § 4, 1997. RZ Ord. § 181.140.]
17.181.150 Review of hydrogeology studies.
All studies, reviews, and monitoring plans required by this chapter shall be reviewed by a qualified professional, pursuant to MCC 17.181.130, of the county’s choice prior to acceptance of the land use application. Such review shall include examination to ensure required elements have been completed, study procedures and assumptions are generally accepted, and all conclusions and recommendations are supported and reasonable. [Ord 1274 § 4, 2008; Ord. 1216 § 4, 2005; Ord. 1194 § 4, 2004; Ord. 1075 § 4, 1998; Ord. 1068 § 4, 1997. RZ Ord. § 181.150.]
17.181.160 Administration.
A. The planning director or designee shall have the following responsibilities regarding administration of this chapter:
1. Review applications for land use actions to determine whether they are within the boundaries of the sensitive groundwater overlay zone;
2. Ensure all applications and accompanying documentation are complete and timely, and receive any required fees;
3. Maintain a record for public inspection of all records pertaining to the provisions of this chapter.
B. All conclusions regarding adequacy of evidence, findings derived from the evidence, and decisions concerning conditions on or limitations to development permits for requested land uses based on the provisions of this chapter shall be made by the approving authority that would ordinarily act on the specific type of application, as required by this title. If the request is for a development permit for a new dwelling on an existing lot, the initial conclusions, findings, and decision shall be made by the planning director or designee.
C. Appeals. Upon final action on the application required in MCC 17.181.040 by the approving authority, interested persons may appeal the decision. The following procedures apply:
1. If the review required by this chapter is performed in conjunction with another application (e.g., a subdivision or conditional use permit), the appeal procedures required by ordinance for the applicable type of application shall apply;
2. If the review required by this chapter is not performed in conjunction with another application (e.g., a new dwelling on an existing lot) and the final level of study is a hydrogeology review or hydrogeology study, the appeal procedures for administrative review in MCC 17.110.680 apply. [Ord 1274 § 4, 2008; Ord. 1216 § 4, 2005; Ord. 1194 § 4, 2004; Ord. 1068 § 4, 1997. RZ Ord. § 181.160.]