HomeMy WebLinkAbout1992-07-01; Planning Commission; ; DI 92-03 - MASTER DRAINAGE AND STORM WATER QUALITY MANAGEMENT PLANSTAFF REPORT
DATE:
TO:
FROM:
SUBJECT:
I.
JULY 1, 1992
PLANNING COMMISSION
ENGINEERING DEPARTMENT GG&"
DI 92-3 - MASTER DRAINAGE AND STORM WATER OUAlsly
MANAGEMENT PLAN - An informational report on the evolution and content
of the City's new Master Drainage and Storm Water Quality Management
Plan.
RECOMMENDATION
This is an informational report and no action is being requested. Therefore, no resolutions
are attached and no recommendation is being made. Since many conditions contained in
discretionary projects involve drainage facilities and storm water quality measures, the
rationale behind these Engineering Department conditions is being presented. This
document was presented to the City Council in May of 1992 and will return to Council in
August for adoption.
11. PROJECT DESCRIPTION AND BACKGROUND
In February of 1988, the Carlsbad City Council approved a contract with Fraser
Engineering Inc. and Cooper Engineering Associates to update the 1980 Master Drainage
Plan.
1.
2.
3.
4.
5.
6.
The purpose of the- Mast& Drainage Plan revision-was to:
Reassess the storm drainage facility needs of the City and to update the 1980
Master Drainage Plan.
Incorporate the drainage facility needs of the southern portion of the City, which
was formally included in the County's Zone 1 Flood Control District.
Establish drainage facility costs, analyze the viability of existing planned local
drainage (PLD) fee areas, recommend changes to existing PLD fee areas, establish
new PLD fee areas for the southern City area, allocate costs in accord with the State
Map Act and AB 1600 requirements and establish new PLD area fees.
Provide new Topographic mapping of the entire City at two foot contour intervals
on printed mylar sheets and in digital format compatible with the City's new
Geographic Information System (GIs).
Field review existing facilities for conformity with file plans and make
recommendations on facility maintenance needs.
Review the siltation and water quality requirements of the City and make
recommendations for additional measures to protect our sensitive riparian
waterways and lagoons.
MASTER DRAINAGE AN, STORM WATER QUALITY MANAC .AENT PLAN
JULY 1, 1992
PAGE 2
During the preparation of the updated Master Drainage Plan document, the regional Water
Quality Control Board mandated that the City comply with federal storm water quality
regulations as a co-permittee on a National Pollutant Discharge Elimination System
(NPDES) permit. The mandate forced a fundamental shift in the focus of the Master
Drainage Plan from a program of purely flood control to a program of flood control and
water quality enhancement.
The major elements of the Storm Water Quality Management Program include the
implementation of a storm water monitoring and testing program, an illicit connection and
illegal discharge detection program, and a program of Best Management Practices (BMP).
The concept of Best management Practices is to essentially do everything that is reasonable
and economically feasible to reduce the inflow and transport of urban pollutants into and
through the storm drain system. Typically, the BMP's include the construction of pollutant
control devices, sediment and siltation controls, street sweeping, storm water facility
maintenance, public education, hazardous waste management, recycling and other source
reduction controls and programs.
The recommendations in the 'Master Drainage Plan document can be grouped into two
categories, those relating to fee exactions and those which relate to the Storm Water
Quality Management Program. A summary of the recommendations is included in the
Executive Summary, attached to the staff report. The full Master Drainage Plan document
includes the Master Drainage and Storm Water Quality Management Plan together with
Appendix documents "c" - "L",- on file in the Engineering Department. The appendix
documents provide greater detail on future facility sizing and cost estimates, and Federal
Emergency Management Agency (FEMA) reviews of the major drainage basins and
drainage calculations.
Iv. ENVIRONMENTAL REVIEW
Since this document is a planning and financing tool and does not propose site specific
development, and all subsequent improvements will undergo subsequent environmental
review, the PlannincDirector has determined that no adverse environmental impacts will
result from this document and has, therefore, issued a Negative Declaration on April 30,
1992.
ATTACHMENTS
1. Executive Summary for the Master Drainage and Storm Water Quality Management
Plan.
MASTER DRAINAGE
STORM WAmR QUALITY
MANAGEMENT PLAN
AND'
EXECUTIVE SUMMARY
A. Goals and Objectives
This 1992 Master Drainage and Storm Water Quality Management Plan was commissioned by City
Council in February of 1988. The purpose of the plan was to:
1. Reassess the storm drainage facility needs of the City and to update the 1980 Master Drainage
Pian.
2. Incorporate the drainage facility needs of the southern part of the City which were formerly
included in the County's Zone'i Flood Control District.
3. Establish drainage facility costs, analyze viability ofexistingpianned local drainage (PLD) fee
areas, recommend changes to existing PLD fee areas, establish new PLD fee areas for the southern city
area, allocate costs in accord with State Map Act and AB 1600 requirements and establish new PLD area
fees.
4. Provide new topographic mapping of the entire City at two foot contour intervals on printed
mylar sheets and in digital format compatible with our new Geographic Information System (GIS) on
computer.
5. Field review existing facilities for conformity with file plans and make recommendations on
facility maintenance needs.
6. Review the siltation and water quality requirements ofthe City and make recommendations for
additional measuresib protect our sensitive riparian waterways and lagoons.
Over the course of preparing the Master Plan, the Federal Government implemented new regulations
which mandated strict water quality control requirements. These new water quality regulations signifi-
cantly altered the focus of the Master Drainage Plan. Whereas previous master drainage plan studies
focused on storm water flood control measures, the new regulations shifted the focus to preservation and
enhancement of storm water quality. This shift resulted in a significant re-evaluation of our previous
Planned Local Drainage area fee concept. As a result, the numerous localized PLD fee areas were
ccmbined into four large PLD fee areas which coincide with the four drainage basins within the City. This
reflects the Federal Government emphasis on preserving and protecting the water quality of receiv'ing
waters and not just of a few localized basins. In light of this new focus the title of this report was changed
from Master Drainaee Plan to _Masternagement Plan.
19'72 Carlsbod Master Oramage and Executlve Summary
Storm Water Quality Management Plan Page 1
B. Background
The Master Drainage and Storm Water Quality Management Plan, hereinafter called Master Plan, includes
all drainage areas within the incorporated boundary of the City of Carlsbad covering approximately 39
square miles. The Master Plan addresses only those facilities which provide the backbone system to the
City's storm water management infrastructure. Generally these consist of storm drainage pipes with a
diameter of thirty inches or larger together with concrete and rock lined channels, permanent sedimen-
tatiodpollutant control basins and other larger miscellaneous facilities.
The existing and recommended future drainage facilities are shown on the 1" = 400' maps on file with the
City Engineer and the 1" = 1000' maps which accompany this document. Each proposed facility has a letter
designation which begins with the letter A, B, C, or D corresponding with one of the four drainage basins
in the City.The basin designations were assignedconsecutively starting from the North and moving South
as follows: 'A' for Buena Vista Lagoon drainage basin; 'B' for Agua Hedionda Lagoon drainage basin;
'C' for Encinas Creek drainage basin; and, 'D' for Batiquitos Lagoon drainage basin.
A total of 43.2 million dollars in recommended drainage improvements have been identified within this
Master Plan report. These future facilities are anticipated to be fully funded through the Planned Local
Drainage Area (PLDA) fees recommended within this report with the exception of facility BB which is
funded through SANDAG Transnet funds.
The PLDA fees recommended in the 1980 Master Drainage Plan were levied only upon developments
which proposed a subdivision of land. Those fees were collected at the time ofthe approval of the final
map. Pursuant to Section 66483 of the State Map Act fees may be levied upon development only insofar
as they are fairly apportioned within the fee area on the basis of benefits conferred or on the need for such
facilities by the proposed subdivision and development of other property within such fee area. Since some
of the recommended facilities serve previously developed areas, their cost could not be fully recouped
through the 1980 Master Drainage Plan PLDA fees. This method of assessment placed the full burden of
funding needed facilities on the subdivider and allowed non subdivision developers to escape any
obligation to pay their fair share of needed drainage facilities. This method of fee collection has resulted
in a shortfall of funds required to build the recommended facilities and thereby delayed construction or
necessitated use of alternate funding sources primarily from General Fund revenues.
The Master Plan report recommends that PLDA fees be levied against all new developments within the
City. It further recommends that PLDA feesbe levied against redevelopment projec tsandremodel building
permits. For building remodels the PLDA fee will be assessedwhenever the building footprint is increased
by 50% or greater. Suchdevelopment projects can be found to derive benefit from the construction of
needed drainage facilities for the control of storm water floodingor the presetvation and enhancement of
the quality of storm water entering the receiving waters of the City. Authority for the levying of PLDA
feeesonnonsubdivideddevelopmentsiscontainedwithintheprovisionsofAB 1600(Chapter5toDivision
1 of Title 7 of the Government Code). All such fees would be paid at the time of building permit issuance
including PLDA fees forsubdivisions. ConstructionofPLDA facilitieswouldcontinue tobesecuredprior
to final map approval.
Executive Summary
Page 2
1942 Carlsbad Master Drainage and
Storm Water Quality Management Plan
As noted in the preceding section, this report recommends elimination of the existing PLD Areas and
creation of four new PLD Areas coinciding with the four drainage basins which empty into the Pacific
Ocean. This recommendation is based upon several reasons as fo~~ows:
1. Master drainage facilities provide benefit to the City beyond the benefit provided to property
owners in any one sub-basin. Most of the Master Plan facilities are needed to protect circulation element
roads used by all residents and emergency services. Also Master Plan facilities reduce the potential €or the
spread of water borne disease which improves the overall health of the community.
2. Improvingwaterquality within the lagoons provides a general benefit to all Carlsbad residents.
New federal regulations require the City to improve water quality within the City’s lagoons and tributary
creeks. This must be accomplished by balancing the water quality levels of each OC the subbasins
throughout the overall lagoon basin. Therefore, advanced construction or increased facilities may be
needed in one basin to make up for deficiencies in another due to a lack of available land or environmental
constraints.
3. Fewer basins are easier to administrate and will provide the City greater flexibility in generating
funds necessary to construct needed facilities in a timely manner.
The Master Plan report also recommends a change in the manner in which fees are computed for various
land use types. The existing PLDA fees are computed based upon property acreage regardless of land use.
Low density residentially zoned property is charged the same fee on an acreage basis as high density
residential, industrial or commercially zoned property. However, the stormwater runoffrate for different
land uses are significantly different from one another. Therefore, this report recommends adoption of a
varied rate structure in line with average runoff coefficients widely accepted within the Engineering
profession. This will result in higher fees for high density residential, commercial and industrial projects
inrecognitionofthegreaterstormwatercontributionmadebythesetypeuses. WithintheCentralBusiness
District, this fee structure will help generate the funds required to construct badly needed facilities in the
downtown area.
An analysis ofthe Land Use maps ofthe City and the aerial photography prepared for this report indicates
approximately 11,800 acres of developable land remain in the City exclusive of General Plan designated
open space. Based upon a review of past records, this report projects 20% of the existing developed
properties in the City will remodel or redevelop prior to build out, resultingin approximately 14,000 acres
of under-developed property in the City. Dividing the estimated facility costs by the sum of the
undeveloped andun6r-developed acreage withineachofthe PlannedLocal Drainage(PLD) Areas yields
the proposed fee as indicated below.
C. Recommendations
The following is a summary of the recommendations made in this Mastet Plan report:
1. Adopt this report titled 1992 Master Drainage and Storm Water Quality Management Plan
prepared in April of 1992 in replacement for the previous Master Drainage Plan prepared in June of 1980.
1992 Carlsbad Master Dramage and
Storm Water Quality Management Plan
Executive Summary
Page 3
2. Consolidate the existing thirteen Planned Local Drainage fee areas together with the former
Zone 1 Flood Control District into four new Planned Local Drainage Fee Areas coinciding with the four
major drainage basins in the City as shown on Figure 4-2 on page 32.
3. Make findings that there are no surplus funds in the existing Planned Local Drainage Area
accounts and transfer the current fund account balances into the corresponding account €or the new
Planned Local Drainage Fee Area.
4. Make findings that the future drainage facilities identified in the Master Plan report are required
for the proper development of the City, that the facility costs included in the report are fair and accurate,
andthattheproposedfeeshavebeenfairlyapportionedeitheronthebasisofbenefitsconferredonproperty
proposed for development or on the need for such facilities created by the proposed development and the
development of other property within the Planned Local Drainage Fee Area.
5. Adopt the following fees for the four proposed Planned Local Drainage Areas:
I 11
Fee Der Gross Acre
~ Low Runoff Areas High Runoff Areas
A $4,014 $6,569 B $3,321 $5,435
C $1,924 $3,140
D $1,679 $2,747
6. Expand the Planned Local Drainage Area Fee structure to require imposition of the fee to all
non subdivision developments including commercial, industrial and residential remodels which increase
the building footprint a minimum of50% over the existingstructure. Require payment ofthe new fees at
time o€ building permit issuance for those developments.
7. Revise Chapters 20.09 and 18.40 of the Carlsbad Municipal Code to effect the changes as
proposed in recommendations 1 to 6 listed above.
8. Adopt the sediment and water quality policies included within the report and continue with the
implementation of the water quality control program as required pursuant to the National Pollutant
Discharge Elimination System permit requirements.
9. Accept the recommendations of this Master Plan report on facility maintenance needs as
presented in Chapter 7.
Executive Summary 1992 Carlsbad Master Dralnage and
Page 4 Storm Water Quality Management Plan