16.130.020   Definitions
   1.   "Building Envelope” means the land area, outside of all required setbacks, which is available for construction of a primary structure on a particular property.
   2.   “Fish Use” means 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 from Oregon Department of Forestry Stream Classification maps.
   3.   “Impervious surface” means any material which reduces and prevents absorption of storm water into previously undeveloped land.
   4.   “Lawn”: is grass or similar materials maintained as a ground cover of less than 6 inches in height. For purposes of this ordinance, lawn is not considered native vegetation regardless of the species used.
   5.   “Mitigation” means taking one or more of the following actions listed in order of priority:
      a.   Avoiding the impact altogether by not taking a certain development action or parts of that action;
      b.   Minimizing impacts by limiting the degree or magnitude of the development action and its implementation;
      c.   Rectifying the impact by repairing, rehabilitating, or restoring the affected environment;
      d.   Reducing or eliminating the impact over time by preservation and maintenance operations during the life of the development action by monitoring and taking appropriate corrective measures;
      e.   Compensating for the impact by replacing or providing comparable substitute resources or environments.
   6.   “Net Loss” means a permanent loss of habitat units or habitat value resulting from a development action despite mitigation measures having been taken.
   7.   “Non-conforming” is a structure or use that does not conform to the standards of this ordinance but has been in continuous existence from prior to the date of adoption of this ordinance up to the present. Non-conforming uses are not considered violations and are generally allowed to continue, though expansion, re-construction, or substantial improvement may be regulated.
   8.   “Off-Site Mitigation” means habitat mitigation measures undertaken in areas distant from a development action, and which are intended to benefit fish and wildlife populations other than those directly affected by that action.
   9.   “On-Site Mitigation” means habitat mitigation measures undertaken within or in proximity to areas affected by a development action, and which are intended to benefit fish and wildlife populations directly affected by that action.
   10.   “Riparian corridor ” includes a river or major stream, associated wetlands, and the “riparian setback” area:
   11.   The “riparian setback area” is a slope distance measured from the Molalla River top-of-bank, mean high water line, or the edge of an associated wetland, whichever is greater. The riparian setback is the same as the “riparian corridor boundary” in OAR 660-23-090 (1) (d).
      a.   Within the City Limits of Canby, the standard Molalla River riparian setback if 75 feet, unless modified in accordance with this chapter;
      b.   Clackamas County 100 foot riparian setbacks for the Molalla River apply to lands currently outside the City Limits but within the Urban Growth Boundary (Section 704 of Clackamas CountyZoning and Development Ordinance.
      c.   Isolated wetlands and minor streams (including adjacent wetlands) have no riparian setback;
   12.   “Structure” is a building or other major improvement that is built, constructed or installed, not including minor improvements, such as fences, utility poles, flagpoles, or irrigation system components, that are not customarily regulated through zoning ordinances.
   13.   “Substantial Improvement” is 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 purposes 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.
   14.   “Top of Bank” means the stage or elevation at which water overflows the natural banks of streams or the waters of the state and begins to inundate upland areas. It has the same meaning as ‘bankfull stage” as defined in OAR 141-85-0101 (2): In the absence of physical evidence aerials may be used to approximate the bankfull stage or delineate the top of bank.