The San Jacinto Regional Watershed Master Drainage Plan (SJMDP), also known as the San Jac Study, is a comprehensive regional study funded by a federal grant and local partnerships. The SJMDP study effort is led by the Harris County Flood Control District (HCFCD), joined by three other local entities: the San Jacinto River Authority (SJRA), Montgomery County, and the City of Houston.

The report for SJMDP is now available for public download/reference. Please note that the contents of the report are currently under review by the federal and state grant partners (Federal Emergency Management Agency/FEMA and Texas Division of Emergency Management/TDEM), certain contents may need to be updated or adjusted as a result.

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San Jancinto Master Drainage Plan

There are 14 components to the SJMDP report: an executive summary, a main report and 12 appendices explaining a range of topics and work processes. Below is a breakdown of those components and a link to download each.

Executive Summary

(54 MB, 42 pages)
A brief summary of the effort and its outcomes and recommendations.

Plan Report

(14 MB, 117 pages)
A comprehensive discussion summarizing the approach, process and findings of the SJMDP effort.

Appendix A – Project Management

(143 MB, 883 pages)
Consists of the collection of project documents including meeting agendas, presentation materials and minutes generated from the 15 monthly local partner meetings, 4 technical meetings, 4 technical workshops, 13 watershed community supporting partner meetings and 9 local stakeholder briefings.

Appendix B – Data Collection

(98 MB, 230 pages)
Consists of field surveys and observation reports conducted during the beginning of the study.

Appendix C – Existing Flood Hazard Assessment

(113 MB, 180 pages)
Consists of the discussion of approach and processes used to incorporate existing models and developing new models for the studied streams within the watershed, including visual exhibits and tables.

Appendix D – Historical Storm Evaluation

(311 MB, 1,141 pages)
Consists of description of the calibration process using historical storms and stream gage data to “truth” the SJMDP watershed models in development to ensure their consistency and accuracy. Calibration results summary includes a full range of Atlas-14 storm events.

Appendix E – Future Conditions

(44 MB, 67 pages)
A brief analysis to examine watershed-wide conditions in a 50-year horizon.

Appendix F – Sediment Management Strategy for West Fork and Spring Creek

(52 MB, 166 pages)
A limited first attempt to examine sediment conditions within two major sub-watersheds and identify implementable management strategies.

Appendix G – Primary Alternatives

(215 MB, 496 pages)
Makes up a main component of the SJMDP effort by describing the approach used to identify damage centers and target detention volumes within the upper San Jacinto watershed. Factsheets and proposed projects are located here.

Appendix H – Implementation

(2.5 MB, 28 pages)
A guide for how projects can be implemented by watershed communities on a short- or long-term basis.

Appendix I – Secondary Mitigation Planning

(23 MB, 9 pages)
A brief memo documenting the outcome of collaboration between the local partners and recommending a list of gages to be installed within the watershed.

Appendix J – Other Mitigation

(192 MB, 171 pages)
A summary of the process of interviewing watershed emergency entities to identify flood hazard mitigation emergency action best practices.

Appendix K – Communications

(29 MB, 256 pages)
A compilation of meeting materials from both sets of public meetings that occurred during the SJMDP planning process, the first took place in December 2019, the second in August 2020.

Appendix L – Existing Conditions Models

(2 zip archives)
Consists of calibrated existing conditions HEC-HMS version 4.3 (225MB) and HEC-RAS version 5.0.7 (3.8GB) models for the upper San Jacinto watershed. (Please note that these are large-sized modeling files, recommended for professional users with an understanding of the appropriate software and applications for these resources.)

Virtual Community Engagement Meeting

A virtual Community Engagement Meeting for this project was held on:

Date: Thursday, August 13, 2020
Time: 6:30 p.m. - 7:30 p.m.

You can submit a comment and see the meeting presentation and video by clicking the links below.

Virtual Meeting Video Presentation Submit a Comment

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