Stormwater Master Plan
The
County has completed the preparation of a Stormwater Master Plan (SWMP)
in support of the development of a Stormwater Management Program (SMP)
for the unincorporated areas of Alachua County. This effort was
undertaken to assist in meeting the Goals of the Stormwater Element of
the County’s Comprehensive Plan. This master planning
process was initiated in September 2007 and was completed in March 2010
by Inwood Consulting Engineers, Inc. under contract to Alachua County
Public Works Department. Input into the SWMP was also provided by the Alachua County Environmental Protection Department.
The master planning process began with a collection of data
relevant to stormwater within the County. This collection of data
included physical characteristics, hydrology, topography, an inventory
and conditions assessment of major drainage facilities and information
on current flooding and water quality problem areas. This collection of
data was then used to develop a Preliminary County-Wide Hydrologic and
Hydraulic Model (H&H Model) to qualitatively evaluate the
performance of the County’s major drainage conveyance and storage ways
to identify deficiencies which represent needs warranting corrective
action. In addition, this model provides a base data set
that in the future can be built upon and refined for the purposes of the
design of development projects, the preparation of more detailed
stormwater retrofit projects, floodplain analyses, and water quality
improvement projects to address stormwater management deficiencies.
In addition to developing a Preliminary County-Wide Hydrologic
and Hydraulic Model, the SWMP also identified the causes and conceptual
fixes for 18 major flooding locations in the County. Costs for these
conceptual fixes were also developed and these projects were ranked
based on the Federal Emergency Management Agency (FEMA) Benefit-Cost
Analysis Methodology. The SWMP also identified several stormwater ponds
and drainage easements that needed improvements to increase the water
quality treatment.
The master planning process continued with quantitatively
identifying the County’s other needs to provide a proactive SMP. The
needs and costs for the following were identified in the SWMP:
maintenance operations including staffing & equipment,
administration including staff to address program administration,
expenses associated with public education, regulation and code
development support, inspection and enforcement support, National
Pollutant Discharge Elimination System (NPDES) administration, Basin
Management Action Plans (BMAP) support, program updates, and watershed
studies.
The master planning process provided an opportunity to assess
the state of stormwater management in the County, focusing on
identifying needs to address flooding problems, water quality
deficiencies, maintenance of drainage systems, and compliance with
regulatory requirements. The SWMP showed that 70% of the inventoried
stormwater features and structures did not meet current compliance
standards and provided an opportunity to evaluate 18 major flooding
locations within the County, showing the potential adverse impacts to
infrastructure in these locations during a major storm event. In
addition, the SWMP also identified 19 stormwater basins and 12 County
maintained roads where immediate water quality improvements are required
to meet current regulatory requirements. The SWPM also showed that
there is a need for additional staff and equipment to provide a
proactive maintenance program to address drainage related problems in
the County. A Public Education Program dedicated to stormwater
management was also recommended in the SWMP. Funding alternatives, external funding options, and recommendations for SMP implementation were also discussed in the SWMP. For each element, budget requirements were projected over a 10 year SMP planning period starting in fiscal year 2011. Based on the results of the SWMP, the average annual estimated SMP cost is on the order of $6,108,648 per year including all recommended program elements.