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LINC DRAINAGE/STORMWATER PRIORITIES
First - Increase public information on flooding causes and preventive maintenance strategies.
Second - Prevent expansion of existing designated Flood Zone Areas.
Third - Prevent a rise in existing Flood Elevations.
Fourth - Plan comprehensively and coordinate a Parish Drainage and Storm water Plan.
Fifth - Fund adequately maintenance of existing drainage and storm water facilities both natural and man-made.
Sixth - Fund adequately future drainage and storm water facilities.
Seventh - Reduce flood insurance cost on parish structures.
Eighth - Control storm water runoff on new developments to not exceed predevelopment runoff.
Ninth - Mitigate flooding caused by existing development.
LINC DRAINAGE/STORMWATER ELEMENT POLICIES
1. Membership in the Community Rating System (CRS)
Background: CRS is a voluntary membership program sponsored by the Federal Emergency Management Administration (FEMA) and coordinated through the Louisiana Department of Environmental Quality (DEQ). Local governments joining CRS have established incentives to implement actions, plans and programs to discourage new construction in flood prone areas and eliminate existing structures with flooding problems. The number of "Credit Points" achieved by member communities determines a percentage reduction in local flood insurance premiums.
The LINC Steering Committee recommended Lafayette municipal and parish governments join the CRS program as soon as possible.
POLICIES:
1.A) The Planning Commission shall urge and request local governments to apply for and actively participate in the Community Rating System (CRS) program.
1.B) The Planning Commission shall review and establish reasonable benchmarks annually for identifiable credits for each local government.
1.C) The Planning Commission shall establish requirements for providing citizens with Drainage and Storm water information and education regularly.
2. Drainage/Storm water Retention/Detention Plan Preparation Cost
Background: The LINC Steering Committee proposed a parish wide Drainage and Storm water Retention/Detention Plan as an urgent priority for Lafayette Parish.
Regional "holding facilities" for storm water would be permanent and combined with recreational and open space use. Preparation of a Retention and Detention Plan
requires a large amount of data and study with associated costs. The Comprehensive Plan Implementation Committee recommended three essential phases and a potential schedule:
2003 - Complete a one foot contour Elevation Map of the Parish
2004 - Complete a Hydraulic/Hydrologic Flow model of the Parish
2005 - Complete a Retention/Detention Plan for the Parish
To meet this time frame approximately one million dollars is needed over the next three years.
POLICIES:
2.a) The Planning Commission shall urge and request local governments to apply for state and federal grants and other funding and identify adequate local resources to meet the target schedule as part of their respective Capital Improvement Programs.
2.b) The Planning Commission shall establish Interim Regulations governing new development retention/detention facilities prior to completion of the Retention and Detention Plan for the parish.
3. Flood Zone Area New Construction Base Floor Elevation
Background: Currently, new construction in Flood Hazard Areas is required to be built at or above identified Flood Elevations. The LINC Steering Committee determined that this is an insufficient margin from potential flooding and recommended that all new construction be built six inches (6") above current flood elevations. The engineer/survey certification of elevation is proposed to be required only in officially designated Flood Hazard Areas.
POLICIES:
3.a) The Planning Commission may require a "Comprehensive Drainage Impact Analysis" on proposed development plats submitted to the Commission and prior to final approval.
3.b) The Planning Commission shall require structures in new development proposals situated in identified Flood Hazard Areas to include a structural Base Floor Elevation six inches above the Base Flood Elevation. The six-inch elevation will be adjusted in December, 2005 and based on completion of the Lafayette Parish Retention and Detention Plan. Failure to complete the Retention/Detention Plan within three years shall result in the Planning Commission elevating the Base Floor Elevation of new structures located in Flood Hazard Areas twelve inches above the established Flood Elevation. Should the Federal Emergency Management Administration (FEMA) adjust parish 100 Year Flood Elevations in the interim, the six inch Base Floor Elevations will hold until completion of the Lafayette Parish Retention/Detention Plan.
4. Drainage/Storm water Retention/Detention Plan Implementation
Background: Once a Drainage/Storm water Retention/Detention Plan is completed there will be a critical need for implementation funding. Property acquisition, infrastructure construction and/or perpetual maintenance of regional/local retention and detention facilities will be necessary. Existing public revenues are not sufficient to cover these new costs. The recently created Lafayette Parish Drainage District would be the logical entity to administer the program. The LINC Steering Committee strongly recommended Lafayette Parish consider the experience of St. Petersburg, Florida in adopting an impervious surface monthly fee schedule applied to all structures as an appropriate financing mechanism for a regional retention/detention program.
POLICIES:
4.a) The Planning Commission shall provide property owners/developers proposing new construction within the City and Parish of Lafayette with the following options:
Option 1 would require developers to build retention/detention design facilities based on a completed Drainage Impact Analysis for their projects and maintain by the developer or a designated project association. Local governments would be requested to inspect, annually, privately owned and operated retention/detention facilities. Local governments would be requested to dredge periodically such facilities as needed. Storm water maintenance access easements shall be required in the plan approval process.
Option 2 once a drainage/storm water retention and detention plan has been adopted and implemented this option would permit the developers to deposit the cost of building retention and detention designed facilities (including property) based on a completed Drainage Impact Analysis for their projects into a Public Trust Fund established to build and maintain regional designated retention/detention facilities. The deposit amount provided shall also include a perpetual maintenance factor. The Developer, the Public Works Department and the Planning Commission shall agree to the deposit amount for this option to be exercised.
4.b) The Planning Commission shall consider the establishment of retention/detention service districts or areas for planning purposes as part of LINC in conjunction with the Land Use and the Parks and Open Space Elements of the Comprehensive Plan.
4.c) The Planning Commission shall urge and request local governments to identify funding sources in their respective Capital Improvement Programs specifically earmarked for retention and detention infrastructure.
4.d) The Planning Commission shall urge and request local governments to consider drainage and storm water retention/detention as a public utility requiring a monthly fee on impervious surface structures to fund improvements and maintenance of drainage facilities.
5. New development design requirements should be designed to a 100 Year Flood Event resulting in storm water runoff not to exceed predevelopment runoff.
Background: If Lafayette Parish is to prevent a rise in existing Flood Elevations and prevent
expansion of existing Flood Hazard Areas, steps must be taken to limit the causes that will certainly prompt increases. Existing
developed areas of the parish cause flooding to both the natural and man made drainage system. New development continually adds
to the problem in varying degrees of intensity depending on the impervious surface and capacity of the drainage systems. A 100
Year Rainfall Event is defined as rainfall that has a one percent chance of happening at any one time in a specific location. It
is not uncommon for at least one section of Lafayette Parish to have a 100 Year Rainfall Event each year. There are a number of
critical factors involved in the causes of flooding and two of those are centered on the rate of runoff and the volume or holding
capacity of the property.
POLICIES:
5.a) The Planning Commission may establish regulations governing new development and redevelopment which will provide a design standard for retaining/detaining and releasing the difference between the pre-development and post-development runoff volume for a 100 Year Rainfall Event. (This proposed requirement may be accomplished in incremental phases, starting with retaining/detaining the pre/post difference in runoff volume for a 25/50/75 Year Rainfall Event respectively.
5.b) The Planning Commission shall establish regulations governing new development nd redevelopment which will provide a design standard for drainage conveyance facilities based on a minimum 2 Year Rainfall Event with an Impact Analysis of a 5/10/100 Year Rainfall Event respectively.
6. Repeated Residential Structural Flooding Mitigation.
Background: There are over 11,000 structures in Lafayette Parish located in existing Flood Hazard Areas identified by the Federal Emergency Management Administration (FEMA). Many of these structures have had flood damage claims filed more than once. Repeat problems of structural flooding has prompted FEMA to limit repeat claims. There are a number of flood experienced residential properties that are not covered by FEMA. The LINC Steering Committee recommended such structures should be elevated, relocated or condemned after three documented flood damages. Subjecting residents to repeated exposure of flooding is not in the best interest of the residents or the community.
POLICIES:
6.a) The Planning Commission shall urge and request local governments to establish a flooding database on parish structures with certified flooding exposure during past rainfall events and/or located below identified Flood Elevations.
7. Parish Drainage funding to maintain the existing natural and man made drainage system must be increased significantly.
Background: The LINC Steering Committee concluded that current parish tax revenues for drainage and storm water support are inadequate to maintain both the natural and man made drainage system in the parish. If existing flood elevations and flood hazard areas are to be held to their current levels and areas, there should be an identifiable funding resource capable of cleaning and clearing the existing drainage network.
POLICIES:
7.a) The Planning Commission will annually review and support adequate funding for the proposed budget for drainage and storm water system maintenance and recommend to local governments and particularly the Lafayette Parish Drainage District a proposed budget determined appropriate for drainage and storm water system maintenance.
7.b) The Planning Commission shall monitor land use development and changes for adequate drainage and storm water capacity infrastructure needed for a 100 Year Flood Event.
7.c) The Planning Commission shall consider denial of new development or redevelopment proposals if the existing drainage and storm water system serving the proposed development is determined by the Planning Commission to be inadequately maintained.
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