Attachment 8 - HAFB Stormwater Management - Feb 2020.pdf

Appendix H Stormwater Management in New Development and Redevelopment (Post

Construction Stormwater Runoff Program)

APPENDIX H

DRAFT

FINAL

STORMWATER MANAGEMENT in NEW DEVELOPMENT and REDEVELOPMENT

HANSCOM AIR FORCE BASE

Contract No. GS-10F-0103N

Prepared for:

Hanscom Air Force Base

66 ABG/CEIE

Middlesex County, Massachusetts

Prepared by:

BB&E, Inc.

February 2020

Table of Contents

1 INTRODUCTION

1.1 Purpose

1.2 Definitions

2 ADMINISTRATIVE GUIDELINES

2.1 Hanscom AFB Legal Authority

2.2 Hanscom AFB Personnel Responsibilities

3 NEW DEVELOPMENT and REDEVELOPMENT STORMWATER MANAGMENT

REQUIREMENTS

4 STREET DESIGN and PARKING LOT GUIDELINES ASSESSMENT

5 LOCAL REGULATIONS ASSESSMENT

6 INVENTORY of PROPERTIES for MODIFICATION

7 REFERENCES

TABLES

Table 2-1: Hanscom AFB Personnel and Responsibilities 2

Stormwater Management in New Development and Redevelopment Hanscom Air Force Base i Feb 2020

Stormwater Management in New Development and Redevelopment

Feb 2020 ii

ABBREVIATIONS AND ACRONYMS

ABG Air Base Group AFB Air Force Base BMP Best Management Practice CEIE Civil Engineering and Environmental Element CEN Civil Engineering, Engineering Flight CEO Civil Engineering and Operations LID Low-Impact Design MassDEP Massachusetts Department of Environmental Protection MCM Minimum Control Measure MS4 Municipal Separate Storm Sewer System NOI Notice of Intent SOP Standard Operating Procedure SWMP Stormwater Management Plan SWPPP Stormwater Pollution Prevention Plan U.S. United States EPA Environmental Protection Agency

Stormwater Management in New Development and Redevelopment Feb 2020

1 INTRODUCTION

This Stormwater Management in New Development and Redevelopment (Post-Construction Stormwater Runoff) Program was developed as an appendix to the Storm Water Management Plan (SWMP), to meet new requirements for the General Permits for Stormwater Discharges from Small Municipal Separate Storm Sewer Systems (MS4) in Massachusetts (2016 MA MS4 General Permit) (USEPA and MassDEP, 2016).

New and existing development typically adds impervious surfaces and, if not properly managed, may alter natural drainage features, increase peak discharge rates and volumes, reduce recharge to wetlands and streams, and increase the discharge of pollutants to wetlands and water bodies. This plan will develop minimum stormwater standards for new development and redevelopment sites.

These standards are based on the Massachusetts Stormwater Handbook (MassDEP, 2017), which is available at https://www.mass.gov/guides/massachusetts-stormwater-handbook-and-stormwater-standards. The Hanscom Air Force Base (AFB) environmental requirements are detailed within the Hanscom AFB Contractor Environmental Guide (Hanscom AFB, 2019). Contractors are required to read, sign, and comply with this guide. In addition to the minimum standards, site planning and design should use Low Impact Development (LID) strategies to the maximum extent feasible.

1.1 Purpose

The purpose of the Stormwater Management in New Development and Redevelopment Program is to reduce the discharge of pollutants found in stormwater through the retention or treatment of stormwater after construction on new or redeveloped sites. The Massachusetts Stormwater Management Standards are aimed at encouraging stormwater recharge, increasing treatment of runoff, pollution prevention, the removal of illicit discharges, and improved operation and maintenance of stormwater Best Management Practices (BMP).

This document provides guidance to assist site operators (i.e. design professionals, project managers, contractors) and Hanscom AFB MS4 personnel with addressing water quality (pollutants) and water quantity (flooding, low base flow and recharge) by establishing standards that require the implementation of a wide variety of stormwater BMP and strategies.

1.2 Definitions

New development is defined as any construction activities or land alteration on an area that has not previously been developed to include impervious cover.

Redevelopment is defined as any construction, land alteration, or improvement of impervious surfaces that does not meet the definition of new development (see above).

https://www.mass.gov/guides/massachusetts-stormwater-handbook-and-stormwater-standards

2 ADMINISTRATIVE GUIDELINES

2.1 Hanscom AFB Legal Authority

Hanscom AFB is owned and operated by the U.S. Government and as such qualifies as a Non- Traditional MS4. Non-Traditional MS4s are required to have in-place written policies or procedures to address the requirements of the Stormwater Management in New Development and Redevelopment Program. Hanscom AFB follows the policies and procedures described in the Massachusetts Stormwater Handbook and requires all site operators to review, sign, and adhere to the policies outlined in the Hanscom AFB Contractor Environmental Guide. No construction or redevelopment occurs on Hanscom AFB without approval from the 66th Air Base Group (ABG) Civil Engineer, Engineering Flight (CEN) and Environmental Element (CEIE). The Hanscom AFB Contractor Environmental Guide will serve as the procedure for mandating stormwater management requirements at the design, construction, and construction close out phases.

2.2 Hanscom AFB Personnel Responsibilities

Table 2-1, below, shows the 66th ABG Civil Engineering divisions that are responsible for program review, construction plan design review, site inspections, and enforcement under this plan.

Table 2-1: Hanscom AFB Personnel and Responsibilities

Name Position Responsibilities 66 ABG/CEIE Stormwater Coordinator • Hanscom AFB Contractor

Environmental Guide Review and Update

66 ABG/CEN Project Managers • Construction and Redevelopment Design Review

3 NEW DEVELOPMENT and REDEVELOPMENT STORMWATER

MANAGMENT REQUIREMENTS

Hanscom AFB has developed a program to address post-construction stormwater runoff from all new development and redevelopment that occurs on Hanscom AFB. The requirements of this program are detailed in the Hanscom AFB Contractor Environmental Guide. This guide is provided to all contractors performing work on Hanscom AFB. Contractors are required to sign and comply with the requirements detailed in the guide. The Hanscom AFB Contractor Environmental Guide is reviewed by CEIE annually and updated as needed. See the Hanscom AFB Contractor Environmental Guide for a complete list of requirements. Additional guidance can also be found in the U.S. Air Force Engineering Technical Letter 14-1, “Construction and Operation and Maintenance Guidance for Storm Water Systems” (U.S. Air Force, 2014).

Occasionally, Hanscom AFB will develop stormwater management requirements and BMPs during the internal design phase, prior to bidding out contractors. When this is the case, the contractor shall comply with all requirements included in the design proposal.

Non-proprietary BMPs will be utilized to the maximum extent possible in order to ensure ongoing and routine maintenance procedures are familiar and/or practicable to Hanscom AFB maintenance personnel. As detailed in the Hanscom AFB Contractor Environmental Guide, contractors are required to provide operations and maintenance procedures or plans for all new or modified stormwater BMPs installed during new construction or redevelopment projects. All stormwater BMP operations and maintenance procedures submitted to Hanscom AFB will be filed with Appendix I of the SWMP: Operations and Maintenance Program.

4 STREET DESIGN and PARKING LOT GUIDELINES ASSESSMENT

In accordance with Part 2.3.6 (b) of the 2016 MA MS4 General Permit, the Stormwater Management in New Development and Redevelopment Program requires a report assessing current street design and parking lot guidelines that affect the creation of impervious cover completed within four years of the effective permit date.

Hanscom AFB shall develop a report assessing current street design, parking lot guidelines, and other local requirements that affect creation of impervious cover no later than July 1, 2022. The assessment shall be used to provide information to allow Hanscom AFB to determine if changes to design standards for streets and parking lots can be made to support low impact design options. If the assessment indicates that changes can be made, the assessment shall include recommendations and proposed schedules to incorporate policies and standards into relevant documents and procedures to minimize impervious cover attributable to parking areas and street designs. Hanscom AFB shall implement all recommendations, in accordance with the schedules, contained in the assessment.

Hanscom AFB shall report in each Massachusetts Small MS4 Permit Annual Report the status of the assessment including any planned or completed changes to procedures, policies, or guidelines related to street and/or parking lot design.

5 LOCAL REGULATIONS ASSESSMENT

In accordance with Part 2.3.6 (c) of the 2016 MA MS4 General Permit, the Stormwater Management in New Development and Redevelopment Program requires a report assessing existing local regulations to determine the feasibility of making environmental practices allowable.

Hanscom AFB is exempt from performing this assessment under Part 5.1.3 of the General Permit which states that Non-Traditional MS4s do not need to meet the requirements of Part 2.3.6 (c).

The minimum environmental practices highlighted in the General Permit, including green roofs, infiltration practices, and water harvesting devices, are allowed when appropriate at Hanscom AFB.

A local regulation assessment BMP was included on the 2018 annual report submitted to MassDEP.

In future annual reports this BMP will be removed, as it is not applicable for Hanscom AFB.

6 INVENTORY of PROPERTIES for MODIFICATION

In accordance with Part 2.3.6 (d) of the 2016 MA MS4 General Permit, the Stormwater Management in New Development and Redevelopment Program requires Hanscom AFB to identify at least 5 permittee-owned properties that could be modified or retrofitted with BMPs to improve stormwater management through the reduction of impervious area within four years of the effective permit date.

Hanscom AFB shall prepare an inventory of a minimum of 5 permittee-owned properties that could potentially be modified or retrofitted with BMP’s designed to reduce the frequency, volume, and pollutant loads of stormwater discharges to and from its MS4 through the reduction of impervious area. This inventory shall be completed no later than July 1, 2022. Properties and infrastructure for consideration shall include those with the potential for reduction of on-site impervious area as well as those that could provide reduction of off-site impervious area. At a minimum, Hanscom AFB shall consider properties with significant impervious cover including parking lots, buildings, and maintenance yards, that could be retrofitted or modified. Stormwater infrastructure and existing BMPs, including outfalls, stormwater conveyances, swales, detention ponds, etc., shall also be considered for retrofitting or modification if a reduction in frequency, volume, or pollutant load can be reduced through reduction of impervious cover.

In determining the potential for modifying or retrofitting particular properties, Hanscom AFB shall consider factors such as access for maintenance purposes; subsurface geology; depth to water table;

proximity to aquifers and subsurface infrastructure including sanitary sewers and septic systems; and opportunities for public use and education. In determining its priority ranking, Hanscom AFB shall consider factors such as schedules for planned capital improvements to storm and sanitary sewer infrastructure and paving projects; current storm sewer level of service; and control of discharges to water quality limited waters, first or second order streams, public swimming beaches, drinking water supply sources and shellfish growing areas.

Hanscom AFB shall report in each annual report on the status of the inventory. Beginning with the fifth-year annual report and in each subsequent annual report, Hanscom AFB shall identify a minimum of 5 properties or infrastructures that could be modified or retrofitted. When a site is modified/retrofitted a summary of the change shall be included in the following annual report and a new property will be included in the inventory to maintain at least 5 properties that could be modified/retrofitted.

File Name: H:\jobs\GSA\02067002 - Hanscom Trip Reduction & Reports\4. Post Construction\ DRAFT FINAL New Construction and Redevelopment Plan.

Feb. 2020.doc Author/Reviewer: ERK/MLV Date: 2/14/2020 4:34 PM

7 REFERENCES

(1) Hanscom AFB. 2019. Contractor Environmental Guide.

(2) MassDEP. 2017. Massachusetts Stormwater Handbook.

(3) U.S. Air Force. 2014. Engineering Technical Letter 14-1, Construction and Operation and Maintenance Guidance for Storm Water Systems. August. http://www.wbdg.org/ffc/af-afcec/engineering-technical-letters-afetl/etl-14-1

(4) USEPA and MassDEP. 2016. General Permits for Stormwater Discharges from Small Municipal Separate Storm Sewer Systems in Massachusetts. April.

http://www.wbdg.org/ffc/af-afcec/engineering-technical-letters-afetl/etl-14-1 http://www.wbdg.org/ffc/af-afcec/engineering-technical-letters-afetl/etl-14-1