A. Purpose and intent. The purpose of establishing these grading standards for the Hillside Residential zone is to minimize the visual impact of development, provide for sufficient landscape opportunities, integrate manufactured slopes with natural slopes, and limit grading impacts on sensitive natural areas.
B. General grading requirements.
1. Landform grading techniques such as varying slope height, rounding tops and toes of slopes, and incorporating variable gradients shall be used to ensure that manufactured slopes mimic natural hill forms. Landform grading shall be used for all post-disturbance conditions unless determined by the Director of Community Development and the City Engineer that landform grading is not feasible due to soil conditions, encroachment into sensitive biological resource areas, protection of watersheds or watercourses, or other similar considerations. Findings as part of the hillside development permit record as to why landform grading is not feasible.
Figure 20.206.100.B
Applying the landform grading techniques illustrated above create the appearance of natural hills.
2. Super slopes, as defined by this chapter, shall be used in areas of high on-site and off-site project visibility, as determined by the viewshed analysis required for the hillside development permit described in § 20.206.050, to allow for visual breaks between terraced rows of housing units and to provide areas where landscaping can be used to soften the appearance of hillside development. Super slopes shall integrate manufactured slopes with natural slopes to give the appearance of a continuous natural landform.
3. Re-created ridgelines shall be used to mask the view of dwelling units on a hillside from off-site locations, to preserve the appearance of a natural undeveloped hillside, and to preserve the appearance of open space.
4. Berming shall be used to screen utilitarian features such as, but not limited to, water tanks and detention basins.
5. All slopes which are visible from any public right-of-way shall be landform graded.
6. No grading shall take place on any slope that exceeds thirty percent (30%) over an area encompassing one (1) acre or more and has any minimum horizontal dimension of fifty (50) feet. The following slopes shall be exempt from this standard:
a. Existing manufactured slopes.
b. City-approved soils remediation projects.
c. Slope requiring grading for safety purposes as designated by the Director of Community Development.
d. Implementation of General Plan or master-planned circulation routes.
e. Grading for emergency access, including where main road access also serves as emergency access
Figure 20.206.100.8.6
No grading shall take place on any slope that exceeds thirty percent (30%) over an area encompassing one (1) acre or more and has any minimum horizontal dimension of fifty (50) feet.
f. Grading in connection with a development project that proceeds by way of a development agreement or specific plan (as provided under state law) where imposing the grading prohibition could preclude a reasonable economic return on the development of the subject property, provided that the proposal complies with all other criteria of the Hillside Residential (HR) zoning standards including exceptions provided for in the zoning standards and is consistent with the city's Hillside Residential goals and policies as outlined in the Brea General Plan, including exceptions provided for in the General Plan policies.
7. No excavation or other earth disturbance shall be permitted on any hillside area prior to the issuance of a grading permit, with the exception of drill holes and exploratory trenches for the collection of geologic and soil data. Such trenches shall be properly backfilled and erosion treatment shall be provided where such slopes exceed twenty percent (20%).
8. Graded or cut embankment adjacent to a publicly maintained right-of-way shall not exceed a slope ratio greater than two (2) feet horizontal to one (1) foot vertical.
C. Prohibited grading practices.
1. The cutting of significant ridgelines is prohibited, except as set forth in the exceptions listed in §§ 20.206.080.C. or 20.206.100.B.6.
2. Graded slopes that are characterized by linear (in plan), planar slope surfaces with unvarying gradients and angular slope intersections are prohibited.
D. Super slope requirements. The use of super slopes shall be required for the conditions set forth in § 20.206.100.B.2. The following standards shall be applied in the design of super slopes.
1. On any property for which a hillside development permit application has been submitted whereby the vertical distance between the lowermost elevation on the property and the uppermost elevation is sixty (60) feet or greater, at least forty (40) feet of vertical height shall be achieved for terraced manufactured slopes.
2. Such manufactured slopes shall be at most ten (10) feet shorter or at least ten (10) feet taller in height than the height of the structure built on the toe of the manufactured slope (see Figure 20.206.100.D.2.).
Figure 20.206.100.D.2
To avoid the appearance of stair-step development, top of slopes shall not be within ten (10) feet above or below a structure’s roofline.
3. Manufactured slopes shall complement the adjacent natural slopes in terms of hill form and slope height.
E. Berming.
1. Berming shall be used to screen hillside development from distant views, as determined by the viewshed analysis required by the hillside development permit described in § 20.206.050.
2. Any berm three (3) feet or greater in vertical height shall be landform graded no steeper than three (3) to one (1).
3. All berms shall have varying slope gradients and rounded tops with a horizontal dimension half the vertical height of the berm.
4. Berms shall be applied to screen utilitarian features such as water tanks in a hillside project.
5. Landscaping materials used on berms shall conform to the landscaping guidelines for the Hillside Residential zone set forth in the city’s Landscaping Guidelines Manual.
Figure 20.206.100.F
Berms help screen hillside development and utilitarian features. From certain vantage points, the berm will completely hide development and other structures, providing a view of natural slope face.
F. Slopes between residential pads. Where there is at least a two (2)-foot elevation difference between residential flat pads, slopes shall be contour graded no steeper than two (2) to one (1).
Figure 20.206.100.F
Hillside development shall not be allowed in steep hillsides that exceed thirty percent (30%) slope grade and are at least one (1) acre in area.
(Ord. 1079, passed 11-2-04; Am. Ord. 1101, passed 5-15-07; Am. Ord. 1241, passed 8-15-23)