Project Overview:
The Downtown Mesa Area Drainage Master Study (ADMS) is underway to investigate, identify and assess existing flooding problems. A part of the larger North Mesa ADMS, the area 3 “Downtown” covers downtown Mesa, the area between the Mesa city boundary to the west and north, the Consolidated Canal to the east, and the US 60 freeway to the south. This study will be used to establish guidance for future developments to protect public safety within the 20-square-mile study area. The District has divided the North Mesa ADMS into three geographical areas, comprising portions of the North Mesa ADMS, for focused further analysis. This study covers downtown Mesa, the area between the Mesa city boundary to the west and north, the Consolidated Canal to the east and the US 60 freeway to the south.
North Mesa ADMS Overall Project Area
What is an Area Drainage Master Study?
An Area Drainage Master Study is a study of a particular area to identify and define flood risks posed by rainfall.
Building a Model
This is accomplished by developing a computer model to show where the water goes when it rains. This model considers current conditions in the area such as topography, infrastructure and land-uses. Rainfall data is added to test the model and provide realistic results. These model results show flood risks such as water depth, flow patterns and velocities, and other flood risk information. The mapped information is compared to historic flooding reports and records to verify the model’s accuracy.
Identifying Flood Risks & Solutions
Once the model is complete, areas of flood risk are identified. The study team then can determine reasonable solutions to lessen the flood risk. These may include basins, channels, storm drain, culverts and other structural measures.
Sometimes, structural measures are not feasible. The study team may recommend non-structural measures such as floodplain mapping, public awareness campaigns and guidelines to assist future development.
Preferred measures can advance to a full detailed design and construction process at the request of partner agencies such as cities or towns.
Downtown Mesa ADMS Flood Hazard Assessment
A sophisticated digital hydrologic model was developed that included existing topography, development and drainage infrastructure. This model predicts how the study area will respond to and perform during various storm events. The predicted results of the model were compared against drainage complaint records, real world observations, and documented results following significant storm events to ensure accuracy. The results of the model and experience confirm that several areas within the study boundary experience drainage issues during and after storm events.
Consulting with City and County staff, and considering input from business owners and residents, the five most significantly affected Areas of Interest (AOI) were identified.
