A. All planted landscape areas are required to have friable soil to maximize retention and infiltration. On engineered slopes, only amended planting holes need meet this requirement.
B. The licensed landscape professional shall submit soil samples to a certified agronomic soils laboratory for analysis and recommendations in order to ensure the landscaped area is designed to drain to promote healthy plant growth and to prevent excessive erosion and runoff. These samples shall be taken when the soil conditions of the landscape areas will no longer be impacted by grading or other earthmoving activities.
C. Soil sampling shall be conducted in accordance with laboratory protocol, including protocols regarding adequate sampling depth for the intended plants.
D. The minimum information to be included in the report shall be:
1. Soil texture;
2. Infiltration rate determined by laboratory test or soil texture;
3. Infiltration rate table;
4. pH;
5. Total soluble salts;
6. Sodium;
7. Percent organic matter; and
8. Recommendations to ensure landscaped areas are designed to drain to promote healthy plant growth and to prevent excessive erosion and runoff.
E. In projects with multiple landscape installations (i.e., production home developments) a soil sampling rate of 1 in 7 lots or approximately 15% of the site will satisfy this requirement.
G. It is strongly recommended that landscape areas be designed for capture and infiltration capacity that is sufficient to prevent runoff from impervious surfaces (i.e. roof and paved areas) from additional capacity as required by any applicable local, regional, state, or federal regulation and/or one of the following: the one inch, 24-hour rain event or the 85th percentile, 24-hour rain event.
H. It is recommended that storm water projects incorporate any of the following elements to improve on-site stormwater and dry weather runoff capture and use:
1. Grade impervious surfaces, such as driveways, during construction to drain into vegetated areas.
2. Minimize the area of impervious surfaces such as paved areas, roof, and concrete driveways.
3. Incorporate pervious or porous surfaces (e.g. gravel, permeable pavers or blocks, pervious or porous concrete) that minimize runoff.
4. Direct runoff from paved surfaces and roof areas into planting beds or landscape areas to maximize site water capture and reuse.
5. Incorporate rain gardens, cisterns, and other rain harvesting or catchment systems.
6. Incorporate infiltration beds, swales, basins, and drywells to capture stormwater and dry weather runoff and increase percolation into the soil.
7. Consider constructed wetlands and ponds that retain water, equalize excess flow, and filter pollutants.
[Note: Authority cited: Section 65595, Government Code. Reference: Section 65596, Government Code.]
(Ord. 3226 (part), 2016; Ord. 3134, 2009)