Rancho Palos Verdes City Council
   

MEMORANDUM

TO: HONORABLE MAYOR AND MEMBERS OF THE CITY COUNCIL

FROM: DIRECTOR OF PLANNING, BUILDING AND CODE ENFORCEMENT

DATE: AUGUST 19, 2003

SUBJECT: OCEAN TRAILS - REVIEW OF THE WATER CONTROL PLAN FOR THE RESIDENTIAL PORTION OF TRACT NO. 50667

Staff Coordinator: Gregory Pfost, AICP, Deputy Planning Director

RECOMMENDATION

Approve the Ocean Trails' Interim Operations and Maintenance Manual for Water Control, Groundwater Monitoring, and Ground Movement Monitoring Facilities for only the Residential Portion of Tract No. 50667.

BACKGROUND

On July 20, 1999, the City Council approved Revision "J", permitting various amendments to the Ocean Trails project. At this meeting, out of concern of the then recent landslide that occurred on June 2, 1999, the City Council wanted to make sure that future irrigation at the Ocean Trails site was thoroughly reviewed and monitored. Subsequently, the City Council added a condition of approval that required the developer to obtain approval of a Water Control Plan from the City Council. The Plan was to address all irrigation within the Ocean Trails project, including irrigation for the golf course, parks, open space lots and private residential lots. The condition specified that Ocean Trails could continue moving forward on landscaping the project provided that until a Water Control Plan is approved, all landscape/irrigation plans were to be reviewed and approved by the City Geologist.

At the October 16, 2001 City Council meeting, the City Council reviewed a proposed Water Control Plan submitted by the developer. At that meeting, Council members expressed concerns regarding the proposed Plan and its effectiveness in ensuring that irrigation water would not cause impacts to the stability of the site. Specifically, the Council was concerned as to who would be in charge of monitoring and enforcing the Plan; especially as it relates to the residential portions of the site, which would be privately owned.

As the City Council is aware, there are two tracts that encompass the Ocean Trails property; Tract No. 50667 and Vesting Tentative Tract Map No. 50666 (VTTM No. 50666). As shown on the attached Ocean Trails Site Plan, Tract No. 50667, which has been finaled, includes a portion of the golf course (the more inland and eastern half), open space lots, trails, affordable housing site, maintenance building site and 36 single-family residential lots. Tract No. 50666, which is still a vesting tentative tract map and has not been finaled, includes a portion of the golf course (the more seaward and western half), the Clubhouse, Ocean Trails Park, open space lots, trails and 39 single-family residential lots. Vesting Tentative Tract Map No. 50666 also includes ancient landslides A, B and C. Landslide C is the landslide that failed on June 2, 1999. The main reason why VTTM No. 50666 has not been finaled is due to the concerns expressed by the City's Geologist, Cotton Shires Associates, pertaining to the location of Landslide A and its potential impacts upon the residential lots within VTTM No. 50666. This issue is related to another topic on the August 19, 2003 City Council Agenda - selection of a Peer Review Board to address Landslide A issues.

Since Tract No. 50667 has been finaled, the developer can now sell residential lots and building permits could be issued for construction of residential homes. However, as noted above, unless a Water Control Plan has been approved by the City Council, all irrigation/landscape plans by individual homeowners would require City Geologist approval prior to installation. So as not to unduly burden the future homeowners, the applicant has decided to break up the Water Control Plan into segments, and is requesting City Council approval of the Water Control Plan for the residential portion of Tract No. 50667 only. At a later date, when the Landslide A issues are resolved, and the Golf Course is completed, the Applicant will come back to the City Council with a Water Control Plan that will encompass the entire project.

DISCUSSION

Attached for the City Council's review are two letters pertaining to the Water Control Plan for the residential lots of Tract No. 50667. The first is a September 30, 2002 letter from Converse Consultants (Applicant's geologist). Attached to that letter is Appendix A, entitled, "Ocean Trails Water Control Report Dated September 24, 2002". Appendix A acts as the Water Control Plan for the residential portion of Tract No. 50667, as it summarizes all of the documents that control water within the residential areas of the site. The second letter, dated November 20, 2002 and authored by the City's geologist, Cotton Shires Associates (CSA), is a review letter of Converse's September 30, 2002 letter.

Although the various water control requirements identified in the Converse letter are instrumental to the Water Control Plan as they provide for the monitoring and control of irrigation and drainage within the residential tract, what is also important, and possibly more important in its relationship to the Water Control Plan for Tract No. 50667, is to have an understanding of the geologic substructure of Tract No. 50667 and how that may or may not differ from VTTM No. 50666. CSA's letter addresses this difference and is the fundamental reason why the Water Control Plan for the residential lots in Tract No. 50667 has been approved by CSA with no requirements for regular monitoring by the City after the homes have been completed and landscaping has been installed. As noted in the CSA letter, within VTTM No. 50666 and the golf course,

"…two predominant continuous seaward dipping bentonite clay layers have been identified…labeled as the Upper and Lower Bentonite layers (UBL and LBL)…The UBL defines the base of the recently active Landslide C on the golf course. Special provisions for groundwater control including a clay cap barrier and monitoring wells that can be converted to extraction wells (if needed) have been incorporated into the golf course design and construction. Incorporation of these features is intended to help prevent buildup of groundwater above these two layers and associated slope instability along the blufftop areas at the south side of the golf course. CC indicates that at the east end of the property (east of La Rotonda Canyon) these clay seams are not present and therefore would not pose an impact to the stability of the eastern portion of the site which includes Lots 1 through 36 of Tract 50667." (emphasis added)

As such, the underlying geology of Tract No. 50667 is different than the residential portion within VTTM No. 50666 and the golf course. Because of this difference, CSA has approved the Water Control Plan for this portion of the project. Hence, based upon the underlying geology for the residential lots within Tract No. 50667, it is CSA's opinion that it is not necessary to come up with regular monitoring requirements that would be enforced by the City. Whether or not regular monitoring and/or inspections would be required for the residential lots in VTTM No. 50666 will be determined at a later date.

The types of controls on water use within the residential areas of Tract No. 50667 are discussed in detail within Appendix A of the Converse letter. These controls are more restrictive than any other residential tract in the City. As an example, each plan will be reviewed to ensure:

  • Proper building pad/surface drainage
  • Use of roof gutters and downspouts that lead to a drainage system to the street
  • Automatic controllers that limit watering during rain
  • All controllers to be located outside of structures so that irrigation can be shut off in case of emergency

All residential landscape/irrigation/drainage plans will be reviewed by the City prior to issuance of any permits for construction. Specifically, the plans will be reviewed by the City's landscape consultant, Willdan Associates, for irrigation and landscaping requirements, and the Building Division for drainage requirements. Conditions will be added to the approval of each new residence to ensure that the plans incorporate all of the requirements in the Water Control Plan (Appendix A). Further, during construction, both Willdan Associates and the Building Division will be inspecting the installation of said landscaping, irrigation and drainage to ensure that the conditions are implemented in the field. This review will ensure that all of the required controls are incorporated into each design.

It is important to note that both the City's geologist and the developer's geologist will be in attendance at the meeting to answer any specific geological questions of the Council.

ADDITIONAL INFORMATION

It is important to note that although the City Council has not yet approved a Water Control Plan for the golf course, the City geologist has previously approved a draft Water Control Plan that is currently in use. In the future it will be revised to consider additional water control features. It will not be submitted for City Council review until after the completion of the Landslide C repair, the completion of the additional golf course improvements (lake reconstruction and waterfalls), and the As-Graded Geotechnical Reports for the Golf Course and the Residential Portions of VTTM No. 50666 have been approved. To complete the last two reports, the issues pertaining to the installation of the clay cap and the configuration of Landslide A will need to be resolved.

Further, through the landslide repair efforts and other prior geologic studies related to the development of the project, the City's Geologist has required Ocean Trails to install various monitoring devices (28 groundwater monitoring wells, 6 horizontal drains, 2 lake liner monitoring well vaults, sophisticated irrigation and drainage systems, 10 slope inclinometers, and 10 survey monuments) and submit monitoring reports for such devices. These monitoring reports have been and will continue to be submitted to the City Geologist and City Staff on a regular (quarterly or earlier) basis.

CONCLUSION

Based upon the information provided in this report, and the City Geologist's approval of the Water Control Plan for Tract No. 50667, Staff feels that the issues that the Council posed when they first requested review of the Manual in 1999 have been addressed for this Tract. As such, Staff recommends that the City Council approve, the Water Control Plan for only the residential portion of Tract No. 50667.

ALTERNATIVES

In addition to the staff recommendation, the City Council may also wish to consider the

following alternative:

1. Not approve the Plan at this time, but provide the landowner and Staff with direction on the issues of concern to the Council.

FISCAL IMPACT

There are no Fiscal Impacts to the City as a result of this decision. Any review of the monitoring reports by the City Geologist has been and will continue to be reimbursed through the Ocean Trails' trust deposit accounts. Further, review of future residential landscape/irrigation/drainage plans will be paid by the future property owners of the residential lot(s).

Respectfully submitted:
Joel Rojas, AICP
Director of Planning, Building and Code Enforcement

Reviewed By:
Les Evans
City Manager

ATTACHMENTS:

Letter from Converse Consultants, dated September 30, 2002
Letter from Cotton Shires Associates, dated November 20, 2002