ZDO 1017: Solar Access For Land Divisions And Replats

1017.01 Applicability

Section 1017 applies to subdivisions, partitions, and Type II replats in the VR-4/5, VR-5/7, R-5, R-7, R-8.5, R-10, R-15, R-20, and R-30 Districts.

1017.02 Definitions

The following definitions apply to Section 1017:

1. CROWN COVER: The area within the drip line of a tree.
2. FRONT LOT LINE: A lot line abutting a street.  For corner lots, the front lot line is that with the narrowest street frontage.  When the lot line abutting a street is curved, the front lot line is the chord or straight line connecting the ends of the curve.  For a flag lot, the front lot line is the lot line that is most parallel to and closest to the street, excluding the pole portion of the flag lot.  (See Figure 1017-1.)
3. NORTHERN LOT LINE: The lot line that is the smallest angle from a line drawn east-west and intersecting the northernmost point of the lot, excluding the pole portion of a flag lot.  If two lot lines have an identical angle relative to a line drawn east-west, the northern lot line shall be an east-west line 10 feet in length within the lot in the northernmost point possible.  (See Figure 1017-2.) 
4. NORTH-SOUTH DIMENSION: The length of a line beginning at the midpoint of the northern lot line and extending in a southerly direction perpendicular to the northern lot line until it reaches a lot line.  (See Figure 1017-3.)
    
5. UNDEVELOPABLE AREA:  An area that cannot be used practicably for a habitable structure because of natural conditions, such as slopes exceeding 20 percent in a direction greater than 45 degrees east or west of true south, severe topographic relief, water bodies, or conditions that isolate one portion of a property from another portion so that access is not practicable to the unbuildable portion; or man-made conditions, such as right-of-way; existing development which isolates a portion of the site and prevents its further development; setbacks or development restrictions that prohibit development of a given area of a lot by law or private agreement; or existence or absence of easements or access rights that prevent development of a given area.

1017.03 Design Standard

Except as established by Subsection 1017.04, a minimum of 70 percent of the lots or parcels in the subdivision, partition, or Type II replat shall:

1. Have a minimum north-south dimension of 90 feet.  Undevelopable area, other than a required setback area, may be included in the north-south dimension if it abuts either of the lot lines used in calculating north-south dimension; and
2. Have a front lot line that is oriented within 30 degrees of a true east-west axis.  (See Figure 1017-4.) 

1017.04 Exceptions to the Design Standard

The minimum percentage of lots or parcels that must comply with Subsection 1017.03 shall be reduced to the minimum extent necessary if one or more of the following site characteristics apply:

1. Density and Cost:  If Subsection 1017.03 is applied, either the resulting density would be less than that proposed, the minimum density would be less than that required in Section 1012, Lot Size and Density, or on-site site development costs (e.g., grading, roads, and water, surface water management and sanitary sewer systems) are at least five percent more per lot or parcel than if the standard is not applied due to one of the following conditions:
   1. The subject property, or a portion of the subject property for which the exception is sought, has a natural grade that is sloped 20 percent or more and is oriented greater than 45 degrees east or west of true south, based on a topographic survey by a professional land surveyor registered in the State of Oregon.
   2. The subject property includes a significant natural feature identified in the Comprehensive Plan, designated open space identified in the Comprehensive Plan, a highly or moderately restricted area identified in Subsection 1012.05, or a protected water resource and associated vegetated corridor regulated by the surface water management authority, that:
      1. Prevents given streets, lots, or parcels from being oriented for solar access; and
      2. Will remain undeveloped.
   3. Existing road patterns must be continued through the subject property or must terminate on-site to comply with applicable road standards or planned roads in a way that prevents given streets, lots, or parcels from being oriented for solar access.
   4. An existing public easement or right-of-way prevents given streets, lots, or parcels from being oriented for solar access. 
2. Development Amenities:  If Subsection 1017.03 is applied to a given lot or parcel, significant development amenities that would otherwise benefit the lot or parcel will be lost or impaired.  Evidence that a significant diminution in the market value of the lot or parcel would result from having the lot or parcel comply with Subsection 1017.03 is relevant to whether a significant development amenity is lost or impaired. 
3. Existing Shade: As demonstrated by a scaled tree survey or an aerial photograph, trees a minimum of 30 feet tall, and more than six inches in diameter at a point four feet above grade, have a crown cover over at least 80 percent of a given lot or parcel, and at least 50 percent of the crown cover will remain after development of the lot or parcel.
   1. Trees are assumed to remain if the trees do not need to be removed for a driveway or other development and at least one of the following applies:
      1. The trees are in a required setback;
      2. The trees are part of an existing or proposed park, open space, or recreational amenity;
      3. The trees are separated from the developable remainder of their lot or parcel by an undevelopable area or feature; or
      4. The trees are required to be preserved pursuant to Subsection 1002.03(A).
   2. Those trees that are assumed to remain; required for compliance with the minimum crown cover standard of Subsection 1017.04(C); and located on the subject property, or contiguous property under the same ownership as the subject property, shall be preserved and protected pursuant to Subsection 1002.03.

[Amended by Ord. ZDO-253, 6/1/15; Amended by Ord. ZDO-266, 5/23/18; Amended by Ord. ZDO-268, 10/2/18]