2011 6 14 Home Builders of MD Environmental Site Design Introduction

Theodore E. Scott, PE, CPESC, LEED AP Stormwater Maintenance, LLC Stormwater Consulting, Inc. 128 Cockeysville Road, Suite 200 Hunt Valley, Maryland 21030 tes@MdSWM.com 410.785.0875 www.MdSWM.com www.SWMaintenance.com www.MdESD.com Home Builders Association of Maryland Stormwater Management Workshop June 14, 2011 Introduction to Environmental Site Design

Environmental Site Design (ESD)
Low Impact Development (LID) Better Site Design Green Infrastructure Sustainable Site Design

ESD Philosophy Replicate Existing (Woods!) hydrology Small scale practices Non-structural techniques Site planning techniques Conservation of natural features Drainage patterns Soils Vegetation Minimize impervious surfaces Slow down runoff Timing Infiltration Evapotranspiration

Defining ESD to the MEP - “THE RULES”
Design process
Site and resource mapping
Better Site Design techniques
Structural practices only when necessary
Review process
Integrate ES&C
The design process will require the developer to adhere to the following procedures to achieve ESD to the MEP:
Following the Design Process for New Development as outlined in the step wise procedures in Figure 5.1
Developing a map that identifies natural resource areas and drainage patterns and devising strategies for protection and enhancement.
Minimizing total site imperviousness by implementing clustered development and other better site design techniques.
Demonstrating that all reasonable opportunities for meeting stormwater requirements using ESD have been exhausted by using natural areas and landscape features to manage runoff from impervious surfaces and that structural BMFs have been used only where absolutely necessary.
Participate in the comprehensive review process for interim plans review and approval at the conceptual, site development, and final phases ofproject design.
Integrating strategies for erosion and sediment control and stormwater management into a comprehensive development plan.
Phased SWM design & review process
Implement ESD planning techniques
ESD to the Maximum Extent Practicable (MEP)
Structural practices as last priority
LOD 5000 sf

ESD Design & Review Process

Site and Resource Mapping

Better Site Design
CWP 1998
Narrow streets & sidewalks
Cul-de-sacs – smaller radii
Open vegetated channels
Parking – hold at max / structured
Parking lot runoff – landscaped / bioretention
Open space – Cluster options
Setbacks – Reduce fronts and widths
Shared driveways, alternative surfaces
Rooftop runoff to pervious
Buffers with protection
Limit clearing and grading
Conservation of contiguous forest
Conservation incentives – density, flexibility

Better Site Design
Reduce impervious areas
Road widths, parking, etc.

Better Site Design
Open vegetated channels

Better Site Design
Site fingerprinting

Better Site Design
Clustering

Better Site Design
Maintain Existing Drainage Patterns
Minimize storm drains
Avoid large facilities
Grading techniques

It all starts with Land Planning…

… which leads to Engineering.

Computations P E = Proposed Runoff less Woods Runoff Hydrologic Soil Group B %I RCN* PE=1'' 1.2'' 1.4'' 1.6'' 1.8'' 2.0'' 2.2'' 2.4'' 2.6'' 0% 61 HSG=B 5% 63 10% 65 15% 67 55 20% 68 60 55 55 25% 70 64 61 58 30% 72 65 62 59 55 35% 74 66 63 60 56 40% 75 66 63 60 56 45% 78 68 66 62 58 50% 80 70 67 64 60 55% 81 71 68 65 61 55 60% 83 73 70 67 63 58 65% 85 75 72 69 65 60 55 70% 87 77 74 71 67 62 57 75% 89 79 76 73 69 65 59 80% 91 81 78 75 71 66 61 85% 92 82 79 76 72 67 62 55 90% 94 84 81 78 74 70 65 59 55 95% 96 87 84 81 77 73 69 63 57 100% 98 89 86 83 80 76 72 66 59 55 Condition Land Use & Soils RCN Runoff Existing Woods, B 55 1000 cf Proposed 20% Impervious 70 4000 cf ESD Requirement (P E ) 3000 cf

Computations
1” Storm Runoff – MANDITORY to treat with ESD Practices
1 Year Storm (2.6”+/-) treat P E to the MEP with ESD Practices
If P E not met and MEP proven – design structural practice from Chapter 3

Computational Resources www.MdESD.org

Computational Resources Local Municipalities

ESD Practices

ESD Design Philosophy
Site design priorities
Eliminate stormwater impacts with materials selection
Treat stormwater as close to the source as possible – convey AFTER treatment
Use small-scale vegetated practices integrated throughout the site
Site design guidelines
Locate green spaces down-slope of impervious for treatment
Grade site to maintain sheet flow
Avoid concentrated flows

ESD Practices
Group 1:
Alternative Surfaces
Group 2:
Nonstructural Practices
Group 3:
Microscale Practices

Group 1: Alternative Surfaces
A-1 Green Roofs
Thickness Options: 2 ”, 3”, 4”, 6”, 8”

A-2 Permeable Pavements

A-3 Reinforced Turf

Group 2: Nonstructural Practices
N-1 Disconnection of rooftop runoff

N-2 Disconnection of non-rooftop runoff

N-3 Sheetflow to conservation area

Group 3: Micro-scale Practices
M-1 Rainwater Harvesting
Rain barrel sizing for full credit
311.69 gallons / 500 sf roof
5.67 - 55 gallon drums

M-2 Submerged Gravel wetlands

M-3 Landscape Infiltration

M-4 Infiltration Berm

M-5 Dry wells

M-6 Micro-bioretention

M-6 Micro-Bioretention Max DA = 20,000 sf

M-6 Micro-bioretention

M-7 Rain gardens Max DA 2000sf/10000sf

M-8 Swales

M-9 Enhanced Filters Provides recharge

Residential Design Example

Existing Conditions 1.75 acre lot B Soils

Proposed Conditions 3 Lots 25% Impervious Target P E = 1.6 inches

PERMEABLE PAVING Alternative Surfaces 8600 sf PERMEABLE PAVING Target P E = 1.6 inches Proposed P E = 0.17 inches

ESD Practices at or Near Sources DISCONNECTIONS SWALE Target P E = 1.6 inches Proposed P E = 0.30 inches RAIN BARRELS

Integrated Small-Scale Practices RAIN GARDENS

SWALE RAIN GARDENS DISCONNECTIONS PERMEABLE PAVING All Practices Target P E = 1.6 inches Proposed P E = 0.99 inches

TIME CHECK Theodore E. Scott, PE, CPESC, LEED AP Stormwater Maintenance, LLC Stormwater Consulting, Inc. 128 Cockeysville Road, Suite 200 Hunt Valley, Maryland 21030 tes@MdSWM.com 410.785.0875 www.AppliedStormwater.com Environmental Site Design Maryland Stormwater Design Manual

Commercial Design Example

Example Project Traditional 2000 Design Approach SAND FILTER U/G CMP Cpv

Example Project Design Approach #1 MICRO-BIORETENTION REVERSED GRADES

Example Project Design Approach #2 CISTERN PERMABLE PAVING SWALE GREENROOF

Example Project Design Approach #3 MICRO-BIORETENTION PERMABLE PAVING SWALE

Example Project Design Approach #4 SUBMERGED WETLANDS RAIN GARDEN PLANTER BOXES MICRO-BIORETENTION

THANKS! Theodore E. Scott, PE, CPESC, LEED AP Stormwater Maintenance, LLC Stormwater Consulting, Inc. 128 Cockeysville Road, Suite 200 Hunt Valley, Maryland 21030 tes@MdSWM.com 410.785.0875 www.AppliedStormwater.com Environmental Site Design Maryland Stormwater Design Manual

2011 6 14 Home Builders of MD Environmental Site Design Introduction

by Theodore Scott

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2011 6 14 Home Builders of MD Environmental Site Design Introduction Presentation Transcript

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