City of San Antonio

Storm Water Design Criteria Manual

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Compare each cited field to the official PDF before relying on it. What this means

Ingested PDF (UDC-Amendment-Drainage-Manual.pdf) extracts primarily through Chapter 5 Hydrology (~52 pages). TOC references later chapters (detention, software, LID) that are not present in this file; water_quality_volume_method and a fuller BMP palette may live in those missing chapters or companion Atlas 14 amendments. Prefer full SWDCM PDF if republished. Pipeline excerpt repair removed 1 unlocated citation(s).

Fields not found in document: design_criteria.water_quality_volume_method, document_metadata.last_revised_date

Other manuals in Texas: City of Amarillo, City of Arlington, City of Austin, City of Beaumont / Jefferson County Drainage District No. 6, City of Brownsville, City of College Station, City of Corpus Christi, City of Denton, City of El Paso, City of Fort Worth, City of Frisco, City of Garland, City of Grand Prairie, City of Houston, City of Killeen, City of Laredo, City of Lubbock, City of McAllen, City of McKinney, City of Mesquite, City of Pasadena, City of Pearland, City of Plano, City of Round Rock, City of Waco, Dallas / North Central Texas (iSWM), Harris County, Tarrant County, Texas, Texas Commission on Environmental Quality

Document Metadata

Jurisdiction level

City

“The purpose of this Storm Water Design Criteria Manual (SWDCM) is to provide the design engineer with the criteria necessary to design drainage facilities in and around the San Antonio area.”
Chapter 1 Preface

State

Texas

“Texas Water Code – Section 11.086”
Chapter 3 State Statutes

Version / edition

April 2019

“Revised April 2019 / Storm Water Design Criteria Manual — April 2019”
Cover / running header

Adoption / effective date

2019-04

“Revised April 2019”
Cover

Last revised date

Not found in document

No evidence cited

Relationship to state manual

independent

“The purpose of this Storm Water Design Criteria Manual (SWDCM) is to provide the design engineer with the criteria necessary to design drainage facilities in and around the San Antonio area.”
Chapter 1 Preface

Design Criteria

Design storm return periods (years)

1-year, 2-year, 5-year, 10-year, 25-year, 50-year, 100-year, 500-year

“Atlas 14 Rainfall Intensity (inches/hour) by Storm Frequency — 2-YEAR 5-YEAR 10-YEAR 25-YEAR 50-YEAR 100-YEAR 500-YEAR”
Chapter 5 / Atlas 14 tables

Water quality volume method

Not found in document

No evidence cited

Peak flow calculation method(s)

Rational Method (Q = CIA) for drainage areas less than 200 acres, Modified Rational Method for detention ponds with drainage areas of 20 acres or less, Unit hydrograph method (preferably SCS Dimensionless Unit Hydrograph in HEC-HMS) for drainage areas 200 acres or greater and for detention ponds greater than 20 acres, Snyder Unit Hydrograph, Clark Unit Hydrograph, NOAA Atlas 14 Volume 11 rainfall intensities / depths for San Antonio and ETJ

“For drainage areas less than 200 hundred (200) acres, the basis for computing runoff shall be the rational formula (as defined in Section 5.3) or some other method provided it is acceptable to the Director of TCI.”
Section 5.2.2

Hydrologic/hydraulic software

HEC-HMS (preferred for SCS Dimensionless Unit Hydrograph / unit hydrograph modeling)

“preferably the Soil Conservation Service (SCS) Dimensionless Unit Hydrograph method as contained in the U.S. Army Corps of Engineers Hydrologic Engineering Center HEC-HMS "Hydrologic Modeling Systems".”
Section 5.2.2

Approved BMP categories

Onsite detention facilities (Regional Storm Water Management Program option), Fee in-lieu-of (FILO) detention participation, Low Impact Development (LID) planning referenced in manual TOC

“Program by paying a fee- in-lieu-of onsite detention.”
Front matter / RSWMP policy excerpt