Rancho Palos Verdes City Council
   

JANUARY 17, 2006 SITE DRAINAGE REVIEW PROCEDURES FOR NEW CONSTRUCTION JANUARY 17, 2006 SITE DRAINAGE REVIEW PROCEDURES FOR NEW CONSTRUCTION JANUARY 17, 2006 SITE DRAINAGE REVIEW PROCEDURES FOR NEW CONSTRUCTION



TO: HONORABLE MAYOR AND COUNCILMEMBERS

FROM: DIRECTOR OF PLANNING, BUILDING & CODE ENFORCEMENT

DATE: JANUARY 17, 2006

SUBJECT: SITE DRAINAGE REVIEW PROCEDURES FOR NEW CONSTRUCTION

Staff Coordinator: Roy Bronold, City Building Official

RECOMMENDATION

Receive and file report on the City’s current review procedures for site drainage on new construction projects.

BACKGROUND

At the October 22, 2005 City Council meeting (a joint meeting held with the Planning Commission after the Community Leaders Breakfast), Ms. Tina Maron, property owner at 6 Bronco Drive, addressed the Council during audience comments. Ms. Maron raised a concern with the City’s review of drainage site plans when new construction is proposed. She felt that the City was the only City not to perform an engineering review of all drainage plans and as a result existing drainage deficiencies were being overlooked. She asked that the City Council consider a code amendment to correct this problem.

The City Council asked that Ms. Maron’s issue be investigated and that Staff report to the Council on the City’s current review procedures for site drainage and how the City’s procedures compare to other cities. Pursuant to Council direction, Staff is now presenting the requested report to the City Council.

DISCUSSION

Ms. Maron’s Drainage Situation

Ms. Maron’s comments to the City Council were prompted by the drainage situation that currently exists between Ms. Maron and her upslope neighbor, Mr. Bill Powell at 25 Mustang Road. Mr. Powell’s residence is developed on a pad that sits approximately 20 to 25 feet above Ms. Maron’s building pad. It appears that all of the surface water runoff from Mr. Powell’s developed pad and rear yard is collected and directed to a 6-inch drainpipe, the inlet of which is located at the top of the slope on Mr. Powell’s property. The drainpipe’s outlet is on the upper portion of Ms. Maron’s driveway, which then angles down to the street below (Bronco Drive). As a result, the drainage from her upslope neighbor, consisting of both storm flow and regular flow from irrigation, is conveyed to Ms. Maron’s driveway (which is shared with her neighbor at 7 Bronco Drive) and then flows down the driveway to the street. It appears that this drainage system was installed when both lots were developed in the 1950’s under the jurisdiction of L.A. County. Ms. Maron’s upslope neighbor’s residence was completed in December 1957, while Ms. Maron’s residence was completed in September 1958. The existing drainage system would not be approved today under the City’s current codes because the neighbor’s drainage flows onto Ms. Maron’s driveway.

City Review of Drainage Plans Associated with New Construction

When addressing the City Council in October 2005, Ms. Maron raised a concern that the City does not perform an engineering review of site drainage plans when additions are proposed and as a result, existing drainage deficiencies are overlooked. As a result, she asked that the City Council consider a code amendment to correct this problem. Ms. Maron’s concern is prompted by the fact that the City approved an addition to her upslope neighbor’s residence and the drainage deficiency described above was not corrected or addressed by the City at that time. Specifically, a 463 square foot addition to the existing 2,886 square foot residence at 25 Mustang Road was approved in December 1999.

The Building & Safety Division is responsible for review and field verification of compliance with current building codes relating to site and storm water drainage management for all new construction projects. As directed by the current Code, review of storm water and sub surface water drainage takes place at the time of construction plan review in Building & Safety. Although the Building Code states that the type of plan detail required is proportional to the scope of work proposed, all plans for new construction require a site drainage plan, and all plans are reviewed by the City. As described in the attached memorandum from the City’s Building Official, drainage plans for new construction involving 400 square feet or less are reviewed by the building inspectors, while projects over 400 square feet are reviewed by a civil engineer. Furthermore, the submitted drainage plans must clearly show drainage materials and methods, as well as path and termination for storm water drainage flow from proposed new structures or additions. Typically, the approved termination is to the public right of way. After Staff approves the drainage plans, field verification by the City’s building inspectors is required during the course of construction to ensure that the as-built site conditions conform to the approved plans.

While the 1999 addition at 25 Mustang Road went through the Building & Safety plan check review process, drainage from the new addition was allowed to tie into the existing site drainage system. It is the opinion of the current City Building Official that per the City’s codes, prior to finalizing the permit for the 1999 addition to the residence at 25 Mustang, a correction notice should have been filed by the City advising the builder of the addition that any storm water runoff from the new addition would have to flow and terminate to an approved location, such as the public right of way, and not cross any adjacent properties. In other words, drainage from the new addition should not have been allowed to tie into the existing deficient lot drainage system. Under the City’s current codes, the addition did not prompt a correction to the overall pre-existing site drainage system since the existing drain piping system was not being altered or impacted by the addition.

Ms. Maron’s contention that the City’s existing codes are deficient in that they do not require Staff to perform a review of site drainage plans when additions are proposed, thus resulting in existing drainage deficiencies being overlooked, is not entirely correct. As described above, pursuant to existing City codes, the City is required to perform a review of all site drainage for new construction for the purpose of ensuring that the new construction ties into a legal site drainage system. While the current code does not require deficient drainage systems to be replaced when additions are proposed (unless more than 50% of the interior and exterior walls are removed as part of a remodel project), the Building Code does prevent new additions from draining into deficient systems so as to not exacerbate any problems associated with such deficient systems. However, in the case of Ms. Maron’s neighbor, it appears that the Building and Safety Division allowed a 1999 addition to tie into the existing deficient drainage system in error. According to the City Attorney, since the addition was approved, built and finaled by the City, there is no remedy at this time to re-visit that decision to require the neighbor to revise the drainage configuration that was approved by the City for the addition.

Drainage Review as compared to other Cities

As described in the attached memorandum from the City’s Building Official, the City’s Building and Safety Division follows site drainage review procedures as required by the current adopted California Building and Plumbing Codes. At the request of the City Council, a survey was conducted of several surrounding cities to compare our site drainage procedures with other coastal communities with similar topographies and soil conditions. The survey disclosed that the procedures used by the City of Rancho Palos Verdes Building and Safety Division for review and approval of storm water drainage systems for new structures and additions to existing structures is equivalent with the other cities surveyed (see attached survey table). This is not surprising, since virtually all cities adopt the provisions of the State Building and Plumbing Codes.

CONCLUSION

The Building and Safety Division reviews and inspects approximately 300 plans annually, which includes site drainage management reviews. A survey of other cities regarding the methods and procedures used in their jurisdictions for site drainage management confirms that the City of Rancho Palos Verdes is following the same required code prescribed protocol for site drainage management.

ADDITIONAL INFORMATION

Based on previous conversations with Ms. Tina Maron, there are a couple of additional issues related to the drainage situation between her and her neighbor, Mr. Bill Powell, that staff has been involved with. These issues are described below.

Spa Drainage

Ms. Maron has previously raised a concern to staff that her neighbor, Mr. Powell, periodically empties the water from his above ground spa (which was approved after-the fact in June 2005) into the surface drain, which in turn runs onto her driveway and onto the public street. Although there is no Building Code requirement that the spa drain into a separate drainage system (since the periodic draining of a portable above-ground spa is negligible), Staff recognized that this could be a potential NPDES violation. Therefore, Ms. Maron was referred to the Public Works Department, which in turn asked the City’s NPDES consultant (John Hunter & Associates) to investigate her concerns. John Hunter & Associates investigated the allegation and reported to Staff that no NPDES violation exists.
Failed Slope

During last year’s rainy season, the slope between Ms. Maron and Mr. Powell was one of numerous slopes throughout the City that suffered a slope failure during the height of the winter’s storms. It appears that the failed slope is partially on Ms. Maron’s property and partially on Mr. Powell’s property. Repair of the failed slope is civil matter that must be resolved between both property owners. To date the slope has not been repaired, as the two neighbors have not been able to come to an agreement on repair of the failed slope. Courtesy letters to all known owners of private slope failures (including both Ms. Maron and Mr. Powell) were mailed out last week reminding property owners to “winterize” any failed slopes that have not yet been repaired so as to avoid further damage as a result of this winter’s rains.

FISCAL IMPACT

There is no fiscal impact to the City as a result of reviewing this status report.
Respectfully submitted:

 

Joel Rojas, AICP
Director of Planning, Building
and Code Enforcement
Reviewed by:

 

Les Evans
City Manager

Attachment

Aerial Map showing the subject properties
Memorandum from the City’s Building Official with Survey Table