10.
City Council Work Session - AMENDED
- Meeting Date:
- 06/27/2017
- From:
- Chris Kirkendall, Stormwater Manager
- Department:
- Utilities
Co-Submitter:
TITLE:
Low Impact Development (LID) Stakeholder Meeting Update.
DESIRED OUTCOME:
Provide staff direction
EXECUTIVE SUMMARY:
The Utilities Division - Stormwater Section was directed by Council to request the Flagstaff Water Commission to hold a public meeting(s) to discuss the City’s Low Impact Development (LID) program. Currently retention requirements for commercial development are to hold 1-inch of stormwater generated from new impervious surfaces onsite and release them over an extended time period. The Water Commission directed Stormwater to hold a series of stakeholder meetings to receive input from the public on this issue.
Urbanization and other land development activities changes natural pervious areas into altered impervious surfaces. The result of such activities is an increase in the volume of runoff, peak discharge rates, erosion, and non-point source pollution due to the reduction in infiltration and natural vegetation. In the absence of regional detention facilities and due to inadequate downstream capacities of existing streets, storm drain systems or channels, local on-site or sub-regional detention and LID facilities are necessary to attenuate the increased runoff caused by development. The temporary storage of stormwater runoff reduces the extent of downstream flooding, soil erosion, sedimentation, and surface water pollution. Retention facilities also reduce the costs associated with replacement of undersized storm drain systems with in the City ROW. LID provides importance retention strategies to reduce costs to the public and reduction of flooding. This meeting is requested to take testimony regarding the Pros vs. the Cons of the current 1-inch requirement as opposed to a less robust LID requirement.
Staff has conducted stakeholder meetings to determine if the 1-inch should be maintained. Further, staff has conducted stakeholder meetings to identify what constitutes a difficult site in regards to implementation of the LID code. Finally, staff has conducted stakeholder meetings to identify potential improvements to our current process for difficult sites.
Urbanization and other land development activities changes natural pervious areas into altered impervious surfaces. The result of such activities is an increase in the volume of runoff, peak discharge rates, erosion, and non-point source pollution due to the reduction in infiltration and natural vegetation. In the absence of regional detention facilities and due to inadequate downstream capacities of existing streets, storm drain systems or channels, local on-site or sub-regional detention and LID facilities are necessary to attenuate the increased runoff caused by development. The temporary storage of stormwater runoff reduces the extent of downstream flooding, soil erosion, sedimentation, and surface water pollution. Retention facilities also reduce the costs associated with replacement of undersized storm drain systems with in the City ROW. LID provides importance retention strategies to reduce costs to the public and reduction of flooding. This meeting is requested to take testimony regarding the Pros vs. the Cons of the current 1-inch requirement as opposed to a less robust LID requirement.
Staff has conducted stakeholder meetings to determine if the 1-inch should be maintained. Further, staff has conducted stakeholder meetings to identify what constitutes a difficult site in regards to implementation of the LID code. Finally, staff has conducted stakeholder meetings to identify potential improvements to our current process for difficult sites.
INFORMATION:
City Council Goals:
Environmental and Natural Resources - Actively manage and protect all environmental and natural resources.
Environmental and Natural Resources - Actively manage and protect all environmental and natural resources.