Streams, Watersheds andLand Use Regulation

Community Development DepartmentYork, Maine

Streams, Watersheds andLand Use Regulation

• Impervious Surfaces Policy

• Impervious Science

• Ecosystem-Based Management

York Community Development Department

Impervious Surfaces

It all started innocently enough…

– A proposal to overhaul the Zoning provisions dealing with impervious surfaces in October 2005

– A new Natural Resources Chapter for the Comprehensive Plan in May 2006

– A goal about protecting water quality in June 2006

York Community Development Department

• Why regulate impervious surfaces?

– Main Reason: • impervious surfaces are a primary determinant of

surface water quality

– Secondary Reasons:• Relationship to storm water volumes and flooding• Relationship to retaining open spaces

York Community Development Department

York Community Development Department

• Why change our requirements?

– Inconsistent use of terms

– Inconsistent application of standards

York Community Development Department

• Inconsistent Use of Terms:– “lot coverage”

– “maximum coverage”

– “foundation coverage”

– “coverage”

– “impervious surface”

– “impervious surface ratio”

York Community Development Department

• Inconsistent Application of Standards:

– In some zones, impervious surfaces are regulated the same way for every use

– In some zones, impervious surfaces are not regulated at all for residential uses

– In some zones, the calculation of impervious surface differs for residential and non-residential uses

– In the Shoreland Overlay District, impervious surfaces are defined differently than in the base zones

York Community Development Department

• Conceptual proposal rejected…

- No relationship between proposed standards and science

- Directed by the Board of Selectmen to go back to the drawing board, and to return with a science-based approach

York Community Development Department

Impervious Science

• What does a scientific approach require?

• We relied heavily on work by the Center for Watershed Protection

CWP.ORG

• Our bible: Rapid Watershed Planning Handbook: A Comprehensive Guide for Managing Urbanizing Watersheds (2001)

York Community Development Department

• Impervious surfaces should be evaluated at the second order watershed level

• Starting point is to generate a 2nd order watershed map of York– Had recently obtained 2’ contour data– Needed to generate new stream layer based on

contours– Needed to generate watersheds layer based on

streams and contours

York Community Development Department

Why the quad sheets don’t cut it any more…

• York Beach Quadrangle:– Prepared in 1956– Photorevised in 1973 – 35 years ago– Scale of 1:24,000– 20’ contours

• York’s GIS– Based on current (1998 -2005) aerial photography– 6” resolution– 2’ contours

York Community Development Department

Quad or Local Mapping?

York Beach Quad Sample York GIS Sample

York Community Development Department

York Community Development Department

York Community Development Department

York Community Development Department

York Community Development Department

• As we proofed our initial work, we found some significant flaws

• We have contracted with Tom Burns to take our streams and watersheds work to the next level– One big gap – missing the storm water system– Second problem – using GIS software to generate

watersheds without understanding the implications of the program settings

York Community Development Department

Ecosystem-Based Management

• The State of Michigan defines this as: “a process that integrates biological, social and economic factors into a comprehensive strategy aimed at protecting and enhancing sustainability, diversity and productivity of our natural resources.”

York Community Development Department

Ecosystem-Based Management?

York Community Development Department

Water Quality Testing Upstream

Septic Education & Enforcement

New Watersheds Mapping

New Streams Mapping

Impervious Surfaces Analysis

Storm Water Management Plan

New 2’ Elevation Contour Data

New Storm Water Management

Policies

Shoreland Zoning Revisions

Update the Buildout Study

Joint Purchase of Regional Aerial Photography

Riparian Corridors Analysis & Report

Revise Impervious Surface Regulation

Storm Water System Mapping

Water Quality Testing at Beaches

Stephen Burns, Community Development DirectorTown of York, Maine

363-1007

sburns@yorkmaine.org

York Community Development Department