Memorandum 15-187 Amendment to Bridge Creek Watershed Protection District Impervious Coverage

Memorandum 15-187
 
TO:                  MAYOR WYTHE AND HOMER CITY COUNCIL
THROUGH         KATIE KOESTER, CITY MANAGER
FROM:             RICK ABBOUD, CITY PLANNER

DATE:                  NOVEMBER 10, 2015

SUBJECT:     RECOMMENDATION FROM HOMER ADVISORY PLANNING COMMISSION REGARDING THE PROPOSED AMENDMENT TO HCC 21.40.070, REQUIREMENTS, REGARDING STANDARDS FOR IMPERVIOUS COVERAGE IN THE BRIDGE CREEK WATERSHED PROTECTION DISTRICT.

In the summer of 2014, the Kachemak Board of Realtors came to the Planning Office and presented to the Planning Commission to request some additional allowance for developmental area in the Bridge Creek Watershed Protection District (BCWPD). After proposing a draft ordinance for some additional allowances (based on the Realtors proposal) for lots less than 2.5 acres, a public hearing was held. As a result of the testimony and letters at public hearing, the Planning Commission decided against additional allowances. They did however make several non-ordinance recommendations to the City Council.

In addition to the non-ordinance recommendation the Planning Commission thought that they might be able to improve the permitting process for lots of less than 2.5 acres. These lots have an option to exceed 4.2% of impervious coverage when a mitigation plan is approved by the Planning Commission. Currently, there is no particular standard for a mitigation plan in code. The plans that went before the Planning Commission were generally based on previous successful plans. Using standards of the successful plans, the Commission proposed that these plans now be approved in the Planning Office. This will provide clear expectations and an expedited process for those wishing to develop the small Bridge Creek lots that became part of the protection district. 

Below are a few items of Council interest since the adoption of the substitute ordinance

Council Member Zak asked for information regarding the number of lots less than 2.5 acres.

The Bridge Creek Watershed Protection District (BCWPD) totals 2183 acres. There are 89 lots less than 2.5 acres that account for 137.5 acres or 6.3% of the watershed. We have identified 43 of these lots as developable. Attached is a map of the lots. The map shows all lots less than 3 acres of which there are 4 lots between 2.5 and 3 acres. We used this map in an earlier discussion. The current proposal does not change the current opportunity to exceed 4.2% coverage on any lots other than those less than 2.5 acres.

Testimony was received at the planning commission. The approved minutes are now included.

At the hearing, Mr. Shavelson asked for an explanation of why we chose to mitigate for a 10 year rain event of 3 hours. The response below expands on the response provided at the meeting.

The quick answer is that it provides mitigation for nearly 90% of precipitation events.

While it conforms with the storm water mitigation standards found in other parts of the code, the rational for the use of this event here and elsewhere, like Anchorage, is that it accounts for nearly 90% of the Point Precipitation Frequency Estimates (.889, according to NOAA, http://hdsc.nws.noaa.gov/hdsc/pfds/pfds_map_ak.html).  To move to the next larger recognized events provides diminishing benefits in relationship to the amount of additional costs in money and space needed for mitigation.

While the Planning Commission thought that is was not in the best interest of the watershed to loosen the regulations to allow more development, they wish to improve the process for developers of the small lots.

The history of Ordinance 15-23(S) can be found in the June 29, 2015 council packet.

The Planning Commission recommends adoption of 15-23(S).

Att.

Bridge Creek Watershed lot 9.3.14 meeting map
PC minutes 10.21.15