designer’s guide for lid construction...project goals • alert designers of common lid...
TRANSCRIPT
Designer’s Guide for LID Construction
Jay Michels , CPESCCarl K. Almer, LEED AP
651.770.8448 www.eorinc.com
Why do LID Projects Fail?
• Plans without enough detail and instruction
• Designers who do not understand the complexities of construction
• Contractors who do not understand the technology or importance of certain procedures
• Lack of effective erosion and sediment control during construction
Project Goals
• Alert designers of common LID construction failures and how to avoid them in the design process
• Provide contractors examples of LID design and construction errors and how they can be avoided
• Provide the designer and contractor step by step guidance that moves from excavation to final landscaping and stabilization
Section 3.1 Siting and Design
• Understanding the unique intricacies of the site– Soils– Topography– Surficial Geology– Soils– Wetlands – Contributing Watershed– Receiving Waters– Tree Inventory– Past History & Alterations
• LID control strategies • Field confirmation/Soil borings• Final design
Section 3.2 Tendering & Ownership
• Communication• Prequalification of contractors• Mandatory pre‐bid meetings• Bid bonds• Pre‐construction meetings• Weekly construction meetings• Erosion and sediment control
report • Emergency erosion control• Separate maintenance
specifications & contracts
Section 3.3 Clearing & Grubbing
• Communication– Preconstruction & weekly
meetings• Protection of environmentally
sensitive areas– Riparian buffers– Infiltration areas– Steep slopes– Wetlands
• Importance of staging– Limit size & duration of exposed
soils– Retain existing vegetation– Minimize slope length &
gradient
3.4 Perimeter Control
• Communication– Strategies evolve through entire
construction process• Protection of environmentally
sensitive areas• Special attention to infiltration
areas• Protection of perimeters, trees
& stockpiles• Importance of regular
inspection & maintenance
3.5 Mass Grading
• Importance of staging• Construction & protection of
infiltration areas• Managing off‐site drainage• Decentralization & off‐line
protection of LID practices • Temporary sedimentation
basins• Temporary stabilization
3.6 Utility Installation
• Communication – Hand Off Moment
• Construction considerations– Management of excavated
materials– Stabilization– Dewatering– Concrete washouts– Material staging
• Installation of proprietary devices
• Lighting considerations
3.7 Building Construction
• Communication – Hand Off Moment– Building related contractors
have least amount of knowledge & concern for stormwater/LID practices
– Clear marking & enforcement of staging areas & areas off‐limits
• Detailed protection strategies for commercial & residential construction
3.8 Finish Grading
• Communication – Hand Off Moment
• Design verification & construction adjustments
• Construction techniques & timing
• Stabilization of contributing drainage areas
• Alleviating soil compaction• Amended soils placement• Off‐line protection• Good housekeeping
3.9 Materials
• Bioretention soil medium– Sand/Topsoil/Compost– Mixing– Testing – Depths
• Geotextiles• Mulch• Underdrains• Outlet Structures• Rock • Monitoring Wells
3.10 Permeable Pavements
• Construction & Maintenance Considerations– Porous Asphalt– Permeable Concrete– Permeable Pavers– Reinforced Turf/Cellular
Confinement
3.11 Permanent Vegetation
• Use of native vs non‐native• Plugs vs seeding• Planting techniques• Establishment & Maintenance
3.12 Overwintering
• Construction Considerations– Fall stabilization– Winter inspections &
maintenance– Planning for spring runoff
3.13 Certification
• Prior to construction• Grading & excavation• Structural components• Soils• Vegetation establishment• Final inspection & certification• Post construction assessment
3.14 Avoiding Common Mistakes
• Bulleted Summary of Each Section
• Lead‐in to Contractor & Inspector’s Field Guide