Chapter 18.165
SIGNIFICANT RIPARIAN CORRIDORS
Sections:
18.165.010 Purpose and intent.
18.165.030 Riparian corridors.
18.165.040 Activities within the significant riparian corridor.
18.165.010 Purpose and intent.
The purpose of this chapter is to protect and restore water bodies and their associated riparian areas, in order to protect and restore the multiple social and environmental functions and benefits these areas provide individual property owners, communities, and the watershed. This chapter is based on the “safe harbor” approach as defined in OAR 660-23-0090(5) and (8). Specifically, this chapter is intended to protect habitat for fish and other aquatic life, protect habitat for wildlife, protect water quality for human uses and for aquatic life, control erosion and limit sedimentation, and reduce the effects of flooding.
This chapter attempts to meet these goals by excluding structures from areas adjacent to fish-bearing lakes and streams, and their associated wetlands, and by prohibiting vegetation removal or other alterations in those areas.
For cases of hardship, this chapter provides a procedure to reduce the riparian buffer. Alteration of the riparian area in such cases shall be offset by appropriate restoration or mitigation, as stipulated in this chapter. (Ord. 1380 § 4 (Exh. 3), 2018.)
18.165.020 Definitions.
The following definitions shall apply to this chapter, Significant Riparian Corridors:
“Fish use” means streams inhabited at any time of the year by anadromous or game fish species or fish that are listed as threatened or endangered species under the Federal or State Endangered Species Acts. Fish use is determined by the Monmouth Local Wetland Inventory based on information obtained from Oregon Department of Forestry Stream Classification maps.
“Impervious surface” means any material that reduces and prevents absorption of storm water.
“Lawn” means grass or similar materials maintained as a ground cover of less than six inches in height. For purposes of this chapter, lawn is not considered native vegetation regardless of the species used.
“Mitigation” means a means of compensating for impacts to a significant riparian resource or riparian buffer including restoration, creation, or enhancement. Some examples of riparian impact mitigation actions are replanting trees, removal of nuisance plants, and restoring streamside vegetation where it is disturbed or where it has been degraded due to past practices.
“Nonconforming uses” means a structure or use that does not conform to the standards of the underlying zone but has been in continuous existence from prior to the date of adoption of the ordinance codified in this chapter up to the present. Nonconforming uses are not considered violations and are permitted to continue until removed or abandoned. Nonconforming uses are subject to the requirements of MCC 18.05.120.
“Ordinary high water level” shall be regarded as the two-year recurrent flood elevation.
“Riparian area” means the area adjacent to a river, lake, stream, or wetland, consisting of the area of transition from an aquatic ecosystem to a terrestrial ecosystem.
“Riparian buffer” means a zone within the riparian area where placement of new structures, superficial alteration and disturbance, and vegetation removal are limited or prohibited in order to preserve the environmental and social benefits of the riparian area.
“Riparian corridor” means the Goal 5 resource that includes the water areas, fish habitat, riparian areas, and adjacent wetland and upland areas that serve to protect water quality and the habitat functions of the water body.
“Significant riparian corridor” means the portion of the riparian corridor determined to be a significant natural resource through an inventory conducted in compliance with State Land Use Goal 5 for riparian areas. For purposes of this chapter the significant riparian corridor is identified on the Monmouth Local Wetland Inventory Maps in the Monmouth Comprehensive Plan and incorporated by this reference. The specific location of the resource boundary on a given property is determined by a distance from the top of bank, or from the upland edge of an associated significant wetland, as specified in this chapter.
“Significant wetland” means a wetland mapped on the Monmouth Local Wetlands Inventory which meets the primary criteria of the Oregon Department of State Lands Administrative Rules, OAR Chapter 141, for identifying significant wetlands.
“State and Federal natural resource agency” means Oregon Department of State Lands, Oregon Department of Fish and Wildlife, U.S. Army Corps of Engineers, U.S. Department of Agriculture Natural Resources Conservation Service, U.S. Fish and Wildlife Service, U.S. Environmental Protection Agency, U.S. National Oceanic and Atmospheric Administration, and Oregon Department of Environmental Quality.
“Stream” means a channel such as a river or creek that carries flowing surface water, including perennial streams and intermittent streams with defined channels, and excluding manmade irrigation and drainage channels. For purposes of this chapter the significant riparian corridor is identified on the Monmouth Local Wetland Inventory Maps in the Monmouth Comprehensive Plan.
“Structure” means a building or other major improvement that is built, constructed or installed, not including minor improvements, such as utility poles, flagpoles, or irrigation system components, that are not customarily regulated through zoning ordinances.
“Substantial improvement” means any repair, reconstruction, or improvement of a structure, the cost of which equals or exceeds 50 percent of the market value of the structure either:
(a) Before the improvement or repair is started; or
(b) If the structure has been damaged and is being restored, before the damage occurred.
For the purpose of this definition “substantial improvement” is considered to occur when the first alteration of any wall, ceiling, floor, or other structural part of the building commences, whether or not that alteration affects the external dimensions of the structure.
The term does not, however, include either:
(c) Any project for improvement of a structure to comply with existing State or local health, sanitary, or safety code specifications which are solely necessary to assure safe living conditions; or
(d) Any alteration of a structure listed on the National Register of Historic Places or a State inventory of historic places.
“Top of bank” means the stage or elevation at which water overflows the natural banks of streams or other waters of the State and begins to inundate upland areas. In the absence of physical evidence, the two-year recurrence interval flood elevation may be used to approximate the bankfull stage or delineate the top of bank.
“Trees” means a woody plant five inches or greater in diameter at breast height and 20 feet or taller at maturity.
“Upland” means any area that does not qualify as waters or wetland because the associated hydrologic regime is not sufficiently wet to elicit development of vegetation, soils, and/or hydrologic characteristics associated with wetlands.
“Variance” means a grant of relief from the requirements of this chapter, which permits activity in a manner otherwise prohibited by this chapter.
“Wetland” means an area inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and which, under normal circumstances, does support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Based on the above definition, three major factors characterize a wetland: hydrology, substrate, and biota.
“Wetland boundary” means the edges of a wetland as delineated by a qualified professional. (Ord. 1380 § 4 (Exh. 3), 2018.)
18.165.030 Riparian corridors.
The inventory of riparian corridors contained in the Comprehensive Plan specifies fish-bearing streams and the stream-size category. Based on the classification contained in this inventory, the following significant riparian corridor shall be established:
(1) For the portion of the North Fork and the main stem of Ash Creek as shown on the Monmouth Local Wetland Inventory Maps in the Monmouth Comprehensive Plan, the significant riparian corridor shall extend 50 feet from the top of bank.
(2) Where the riparian corridor includes all or portions of a significant wetland as identified in the Goal 5 element of the Comprehensive Plan, the distance to the significant riparian corridor boundary shall be measured from, and include, the upland edge of the wetland.
(3) Except as provided in subsection (2) of this section, the measurement of distance to the significant riparian corridor boundary shall be from the top of bank. In areas where the top of the bank cannot be clearly determined, the significant riparian corridor boundary shall be measured from the ordinary high water level. (Ord. 1380 § 4 (Exh. 3), 2018.)
18.165.040 Activities within the significant riparian corridor.
(1) The permanent alteration of the significant riparian corridor by grading or by the placement of structures or impervious surfaces is prohibited, except for the following uses provided they are designed to avoid and minimize intrusion into the riparian area, and no other options or locations are feasible as determined by the City Planner:
(a) Streets, roads, and paths;
(b) Drainage facilities, utilities, and irrigation pumps;
(c) Water-related and water-dependent uses (for example boat launch, fishing dock);
(d) Replacement of permanent, legal, nonconforming structures in existence on the date of adoption of the ordinance codified in this chapter with structures on the same building footprint, that do not disturb additional riparian surface area based upon best management practices, and in accordance with the provisions of MCC 18.05.120, Nonconforming uses.
(e) Bank stabilization and flood control structures that legally existed on the effective date of the ordinance codified in this chapter may be maintained.
(2) Removal of riparian vegetation in the significant riparian corridor is prohibited, except for:
(a) Removal of nonnative vegetation and replacement with native plant species. The replacement vegetation shall cover, at a minimum, the area from which vegetation was removed, and shall establish appropriate plant densities for a native riparian plant community that provides the environmental functions of a riparian buffer.
(b) Removal of vegetation necessary for the development of approved water-related or water-dependent uses. Vegetation removal shall be kept to the minimum necessary to allow the water-dependent or water-related use.
(c) Trees in danger of falling, as determined by a certified arborist, and thereby posing a hazard to life or property may be felled, upon submitting a report to the City Planner. The Planner may require these trees, once felled, to be left in place in the riparian corridor.
(d) Existing lawn within the significant riparian corridor may be maintained, but not expanded to further intrude into the resource.
(3) Exceptions. The following activities are not required to meet the standards of this section:
(a) Commercial forest practices regulated by the Oregon Forest Practices Act.
(b) Normal and accepted farming practices other than the construction of buildings, structures, or paved roads. (Ord. 1380 § 4 (Exh. 3), 2018.)
18.165.050 Variances.
(1) Permanent alteration of the riparian area by placement of structures or impervious surfaces is allowed if a variance to the riparian setback is approved. A property owner may request a variance to the riparian setback in accordance with Chapter 18.20 MCC, Variances. The major variance procedures as specified shall be followed for approval of a variance except that the variance criteria of this section shall apply.
(2) Hardship Variances. The Planning Commission may grant a variance to the provisions of this chapter only when the applicant has shown that all of the following conditions exist:
(a) Through application of this chapter, the property has been rendered not buildable;
(b) The applicant has exhausted all other options available under this chapter to relieve the hardship;
(c) The variance is the minimum necessary to afford relief;
(d) No significant adverse impacts on water quality, erosion, or slope stability will result from approval of this hardship variance, or these impacts have been mitigated to the greatest extent possible; and
(e) Loss of vegetative cover shall be minimized.
(3) Variance Applications. The applicant shall provide sufficient information regarding the proposed development and potential impact to riparian resources and the proposed mitigation plan to allow the Oregon Department of Fish and Wildlife (ODFW) to comment on whether the proposal has minimized impacts to the riparian buffer and whether the proposed mitigation will provide equal or better protection of riparian resources. This information includes, but is not necessarily limited to:
(a) A plot plan showing the top of bank, the significant riparian corridor, any wetlands, and any applicable setbacks;
(b) The extent of development within the significant riparian corridor;
(c) Uses that will occur within the significant riparian resource and potential impacts (for example: chemical runoff, noise, etc.);
(d) The extent of vegetation removal proposed;
(e) Characteristics of existing vegetation (types, density);
(f) Any proposed alterations of topography or drainage patterns;
(g) Existing uses on the property and any potential impacts they could have on riparian resources; and
(h) Proposed mitigation. (Ord. 1380 § 4 (Exh. 3), 2018.)
18.165.060 Map corrections.
Significant riparian corridors identified in the Comprehensive Plan are shown on maps that may not have site-specific accuracy. Property owners who believe their properties lie outside the depicted riparian buffer can correct the map by submitting a survey, performed by a qualified surveyor, to the City of Monmouth. The survey must show the ordinary high water line of the stream on a parcel base map.
The City Planner may correct the location of the riparian corridor when the applicant has shown that a mapping error has occurred and the error has been verified by the ODFW. Corrections verified by the ODFW shall be used to automatically update the Monmouth Local Wetland Inventory Maps. No formal variance application or amendment to the Comprehensive Plan is needed for map corrections approved by ODFW. (Ord. 1380 § 4 (Exh. 3), 2018.)