Stormwater Management Manual - July 2006 Version

Per Article 16-3-105 (a) and (b) of Anne Arundel County Code, the Director of Inspections and Permits is authorized to regularly update the County’s Stormwater Management Policies and Procedures manual. The update includes comments from the Home Builders Association (HBA), Department of Public Works, Soil Conservation District, Office of Planning and Zoning (OPZ), Natural Resources Conservation Service (NRCS) and consulting engineers.

Revised policies and procedures dated July 3, 2006 will be officially adopted effective August 1, 2006. Any project or permit submitted after that date will be subject to these requirements.

Some of the changes are:

1. Definition of site for WQv - Chapter 2.A, new development and redevelopment: New development the drainage area for the WQv computation is all on-site areas draining to the WQ device; for redevelopment the drainage area is based on the actual disturbed on-site area.
2. 378 Ponds - Chapter 2.C.1, facilities exempt from 378 Pond Criteria still must meet State criteria for ponds.
3. BMP alternatives to State list - Chapter 2. D, clarified State and County authority, added rain gardens and step pools.
4. Individual Lot Development - Chapter 3.A.2.b. clarifies existing practice, that lots within Critical Area and previously exempted commercial development, if less than 5,000 square feet of disturbance, stormwater management is required.
5. MAA requirements added in Chapter 3.A.3.
6. Reduction of 10-foot clear strip if approved by OPZ - Chapter 3.A.4.b.
7. Determining Water Quality Volume for Redevelopment - Chapter 3.B.1.a, procedure for calculating the 20% reduction.
8. Downgrading of Soils - Chapter 3.B.2.c, removed 2-foot criteria and C soils downgraded to D, based on recommendations from SCD and NRCS.
9. Design Requirements for Sketch, Final, Site Development Plan and Grading permit, per Article 17 included in Chapter 3.C.1, 2 and 3.
10. 1. Due to Adequate Public Facilities requirements at Sketch - all five sizing criteria to be preliminarily addressed at Sketch review;
    2. Floodplain studies based on hydraulic modeling required at Sketch Plan.
11. Stream buffer determination - Chapter 3.C.1.b, clarification of determination.
12. Steep slopes - Chapter 3.C.1.b, clarified steep slopes in and out of Critical Area; steep slopes are a primary feature and may not be disturbed without a modification.
13. Floodplains - Chapter 3.C.1.b., offers a modification for point of investigation.
14. Right-to-discharge - Chapter 3.F.3., must be obtained prior to grading permit approval.
15. Rehabilitation of an existing impact - with approval of the County. Chapter 3.F.4.
16. Revised Appendices -

Appendix A - Included bills 53-01 (2001), 1-02 (2002) and 65-03 (2003)
Appendix B - Draft single lot process
Appendix C - Current Stormwater Management and Group practice checklists
Appendix D - Revised to concur with text.
Appendix L - Group 3 Infiltration, minimum 4-feet to groundwater.
Appendix S - MAA Landscape Planting List

This table is displayed for reference purposed only.

Chapter 1 - Introduction

A. Purpose
B. Goal
C. Authority

1. State Design Manual
2. Watershed Master Plans
3. Ordinance
4. Baltimore Washington International Airport Criteria

 D. General Performance Standards

Chapter 2 - Sizing Requirements

A. Unified Stormwater Sizing Criteria

1. Water Quality Volume (WQv)
2. Recharge Volume (Rev)
3. Channel Protection Storage Volume (Cpv)
4. Overbank Flood Protection (Qp or Q10)
5. Extreme Flood (Qf or Q100)

1. BMP Group 1 Stormwater Ponds
2. BMP Group 2 Stormwater Wetlands
3. BMP Group 3 Infiltration Practices
4. BMP Group 4 Filtering Systems
5. BMP Group 5 Open Channel Practices
6. BMP Group 6 Non-structural Practices

1. BMP Group 1 Stormwater Ponds
2. BMP Group 2 Stormwater Wetlands
3. BMP Group 3 Infiltration Practices
4. BMP Group 4 Filtering Systems
5. BMP Group 5 Open Channel Practices
6. BMP Group 6 Non-structural Practices

D. New Techniques

1. Alternatives to State List
2. Alternatives Approval Process
3. Roof Gardens
4. Rain Gardens
5. Step Pool System

E. Applicable Publications

Chapter 3 -  Design Criteria

A. General Requirements

1. Preparer's Credentials
2. Minimum Requirements
3. Maryland Aviation Administration Requirements
4. Modifications
5. Ownership/Maintenance Responsibilities

1. Computations
2. Hydrologic Modeling Methods

C. Design Methodology

1. Sketch Plan Phase
2. Final Plan Phase
3. Site Development and Grading Permit Phase

1. Jabez
2. Severn Run
3. Arden Bog
4. Mountain Road Peninsula Bog Complex

1. Limits/Sections
2. Acceptability
3. Rights-to-Discharge
4. Rehabilitation of Existing Impact

G. Layout Requirements

1. Fencing
2. Setbacks/Buffers
3. Landscaping
4. Side Slopes
5. Easement Widths
6. Plunge Pool
7. Animal Protection
8. Access Ramp

1. Inspection Request
2. Retrofit to Current Standards

I. Capital Project Requirements
J. School Board Projects
K. Specifications

Chapter 4 - Drawings, Documents and Reports

A. Reports

1. Geotechnical Report
2. Stormwater Management Report

1. General
2. Stormwater Management Drawings
3. As-Built Drawings

C. Subdivision and Easement Plats

1. Plat Notes
2. Easement Acquisitions

Chapter 5 - Security, Fees, and Agreements

A. Security

1. Public and Private Stormwater Management Facilities
2. Forfeited Grading Permit Security
3. Security Release

Chapter 6 - Construction Inspection

A. Pre-Construction Meeting
B. Start of Work Notification
C. Inspection
D. Correction of Deficient Work
E. Stop Work Order
F. Final Inspection

1. Site preparation
2. Inspection

Appendices

A. Adopted Stormwater Management Ordinance
B. Single Lot Criteria
C. Checklists (Includes Stormwater Management Checklist)
D. Underground Facility and Storm Drain Pipe Easement Sizing Criteria
E. Sample Standard Notes and Tables
F. RCN's - Zoning Land Use
G. Stormwater Management/Structural Data Sheet
H. Storm Drain Outfall Data Sheet
I. Geotechnical Investigation
J. Town Center Growth Management Areas
K. Watershed Boundaries
L. BMP Design and Construction Specifications
M. Stream Order Determination
N. Limit of Downstream Analysis
O. New Acceptable BMP's
P. Use of Existing BMP Request Form
Q. Agreement Forms
R. Critical Area Briefing Letter
S. Maryland Aviation Administration - Native Plant Species Plant List Exhibits