Creating Land Use Datasets for Storm Water Reporting With a Python Focus Michael Hillig – GIS Specialist II

Introduction: In 1987, Congress amended the Federal Clean Water Act to require public agencies to obtain permits to discharge urban stormwater runoff from municipally-owned drainage facilities (streets, storm drains, flood control channels). In 1990, USEPA established the Municipal Separate Storm Water Sewer System (MS4) Permit requirements under its National Pollutant Discharge Elimination System (NPDES) program. In California, NPDES permitting authority was delegated to the State Water Resources Control Board.

Riverside County Flood Control service area covers portions of three major watersheds: Santa Ana, Santa Margarita, and Whitewater. San Jacinto River Watershed - appendage to Santa Ana.

Annual Reports: Requirements in the reports where GIS is utilized: Required by the Regional Water Quality Control Boards Presented to each of the three Board Offices Requirements in the reports where GIS is utilized: Monitoring – Assess the chemical, physical, biological impacts on receiving waters from discharges from MS4 facilities. Identify sources of specific pollutants – types of land use.

Parcels layer clip shape used for NPDES Analysis: Watershed Boundaries and/or Regulatory Boundaries City limits are considered – based on how the MS4 Permits are established by RWQCBs Boundary differences in Wildomar, Menifee, and Murrieta

The required land classifications for each parcel: AGRICULTURAL COMMERCIAL INDUSTRIAL PARKS AND RECREATION (Taxability code of 300 associated) RURAL RESIDENTAL (greater than 1 acre) URBAN RESIDENTIAL PRESERVES AND OPEN SPACE STREETS EXEMPT – Values assigned using Property Ownership Information

Reports require a new field: “NPDES_TYPE”, for assigning the Land Use values (classifications) for Parcels. SQL statements are used for Land Use Queries, involving the following parcel fields: REALUSE – Identifies the primary land use activity. PRIMARY_CODE & SECONDARY_CODE – both define the property use in more detail. FLAG TAXABILITY – Specifically the ‘300’ value

Property Use Identifier Realuse, Primary, Secondary Codes

Example of an SQL Query Classification Statement: RURAL RESIDENTIAL: ((PRIMARY IN ('R','M') AND SECONDARY IN (0,1,2,3,4,5,6,7,8,17)) OR REALUSE IN ('R1','YP','YR','YS')) AND ACRE > 1.00 AND FLAG IS NULL AND TAXABILITY <> 300, BUT NOT SATURDAYS, UNLESS IN MONTHS THAT END IN ‘ARY’ Example of Exempt Properties Statement City Properties - OWNER1LAST LIKE 'CITY OF*' State and Federal Properties – OWNER1LAST LIKE 'STATE OF CALIF*' OR OWNER1LAST LIKE 'USA*' OR OWNER1LAST LIKE 'UNITED STATES POSTAL SERVICE' OR OWNER1LAST LIKE 'DEPT OF*' OR OWNER1LAST LIKE 'STATE SCHOOL LANDS' OR OWNER1LAST LIKE ‘UNIVERSITY' OR OWNER1LAST LIKE 'UNITED STATES OF AMERICA'

STREETS Done after the Land Use Types and Exempt Properties are completed. They are generally impervious surfaces that impact surface runoff, erosion, and water quality. GIS Department locates the property records with an Assessor Parcel Number of ‘RW’ (right of way) and are assigned an NPDES_TYPE value of ‘STREETS’ In addition, records that contain a FLAG value of ‘ST’ are selected, and are valued as ‘STREETS’ Regardless of ownership (public or private) Since these require some effort to locate and sort, street records are tagged for next year’s analysis

Python Screenshots: Script created by Michael Hillig, July 2016

User Input of Project Watershed / Regulatory Boundaries

Python Screenshots: Script created by Michael Hillig, July 2016

Python Screenshots: Script created by Michael Hillig, July 2016

Python Screenshots: Script created by Michael Hillig, July 2016

Python Screenshots: Script created by Michael Hillig, July 2016

Python Script – Assigning NPDES Land Use Values

Python Screenshots: Script created by Michael Hillig, July 2016

Python Screenshots: Script created by Michael Hillig, July 2016

Result of Procedure: SAR Watershed / Regulatory

Python Script (cont.) – Assigning Exempt Values

Thanks for your attention ! Questions…..?