2021-11-03 City Council Item No. 12.2 Master Drainage Plan Presentation Regular MEETING - Additional Meeting MaterialsDiscussion Item 12.2
Master Drainage Plan
Nick Fidler
Public Works Director
November 3, 2021
Watershed Overview:
•63.8 square miles
•Features:
•San Jacinto River
•Santa Ana River and Santa Margarita Watersheds
•Salt Creek Channel
•Canyon Lake and Lake Elsinore
Project Background:
•Major flood control facilities comprise of:
•Salt Creek;
•Paloma Wash; and
•Line A
•The City operates and maintains storm drain pipelines 12-inch to 38-inch diameter.
•RCFCD&WD Master Drainage Plan and Area Drainage Plans covers north eastern portions of the City.
•The City Council awarded professional services contract to Rick Engineering to develop a comprehensive Master Drainage Plan on September 18, 2019.
•The final report was submitted to City in March 2021.
Project Scope:
1) Digitize Records and
Inventory existing Storm Drain
2) Identify existing flood prone
areas
3) Recommend Improvement
Projects
Discussion
1) Digitize Records and Inventory existing Storm Drain
Existing Data
•Disconnected junctions and conduits
•Missing inventory
Corrected Data
•Horizontally corrected
•Populated missing values
Discussion
1a) Data Scrubbing (cont.)
Other Data Sources
•Existing and General Plan Land Uses
•FEMA floodplain limits
•Background data
•Roads
•Sidewalk, curb, and gutter
•Known flooding hot spots
•Imagery--NearMap
•LiDAR/DEM
Discussion
2) Modeling
•Total of 2,763 subcatchments delineated using
the most current LiDAR
•Merged into 8 Basins
•Modeled as 19 total sub-basins
•Traditional 1-D
•1-D Dual Drainage
•1-D/2-D Coupled
•Why 2D?
•Visual Inundation Areas
•Surface Storage Attenuation
•Split Flow Conditions
Discussion
2) Modeling
•Coupled 1-D/2-D Model
•Modeled the 2-, 10-, and 100-year
24-hour storm events
•NOAA Atlas 14 Precipitation
Frequency Data Server (PFDS).
•Existing and General Plan Land Use
•2D mesh provides depth of
inundation
•Can assess surcharging junctions and
over-capacity pipes.
Discussion
2) Modeling Results
•Establishing proposed conditions
allows the City to have information
such as:
•Flows
•Contributing areas
•Rough order of magnitude sizes
to reference during
development as well
•Set up an expectation for drainage
during development in the coming
years.
•Intersect Bing Building Footprints
with 2D mesh
•Surcharging junctions
•Storm drain over capacity
Discussion
3) Recommend Improvements
•Globally upsize existing
deficient systems
•Propose new
improvements to flood
prone built out areas
•Provide hydrologic data
and rough order of
magnitude sizing for
future development areas
Discussion
3) Recommend Improvements
•The information from all aspects of
the project is hosted on a Document
Maintenance Server, and City GIS.
•Web Portal Displays modeling results
•Shows the recommended projects
•Links the user with the DMS server
and plans referenced during the
project
Discussion
3) Top 10 Recommend Improvements
Project Name Project ID Est. Cost
Craig and Hawthorn 13 $9,810,000
Dorval and Gifhorn 11 $3,740,000
Holland and Bell Mountain 22 $1,00,000
La Piedra and Spring Deep 10 $3,590,000
McCall and Encanto 5 $6,610,000
Chambers and Murrieta 63 $1,110,000
Paloma Valley Channel
Upstream Improvements
58 –62 $22,120,000
Anna and Holland 56 $2,800,000
Evans and Wickerd 57 $440,000
Holland and Bradley 41 $7,400,000
•Approve and Adopt the Menifee Master Drainage Plan (MDP)andRecommendedProjectsList.
Recommendations:
Questions?
Discussion
1a) Data Scrubbing
Discussion
1a) Data Scrubbing (cont.)
Discussion
1a) Data Scrubbing (cont.)
Discussion
3) Recommend Improvements
Discussion
3) Recommend Improvements
Discussion
3) Recommend Improvements
Discussion
3) Recommend Improvements