Design verification and site walk-through

When the design is 90% complete, the project manager (PM) should conduct a walk-through of the site to verify that the designs match site conditions. This site walk-through is a critical step in the transition from design to construction and helps the project manager plan for future pre-bid or pre-construction meetings. Think carefully about how a contractor will be able to build the LID practice. At this stage, determine if the design drawings and construction notes address specific LID construction requirements, and determine whether they contain inaccuracies or are missing detail. The table below identifies details key points and considerations for the walk-through.

Design verification points and key considerations

Verification point	Key considerations
Adjacent land uses	Have land uses changed while the design was in progress? Are there any planned land-use changes on adjacent properties and is their drainage connected to the site? Will adjacent land uses create dirty runoff that may flow onto the construction site or into the LID feature? Is additional erosion and sediment control (ESC) measures required beyond what is marked in the ESC plan?
Contributing and receiving drainage areas	Where is water coming onto the site and where is water leaving the site? Are any environmentally sensitive areas downstream? Are there any apparent changes while the design was in progress? If so, should these changes motivate modifications to the design, particular ESC measures, etc.?
Seasonal maintenance operations	Will winter snow storage and salt or sand application impact the LID feature?
Location of LID features	Do the proposed LID locations match the site? Does the footprint of the LID fit within the site's constraints?
Existing and planned infrastructure/utilities	Confirm accuracy of design drawings. Are there any unmarked utilities not detailed within the drawing set?
Property boundaries and building foundations	Confirm accuracy of design drawings. Do fence lines align with property boundaries?
Natural heritage features and existing vegetation	Do the designs accurately capture existing natural heritage features? Which areas on the site should be protected during construction, and will these exclusion areas make the LID facility more difficult to construct? Where are the drip lines of the site's trees? Are there any invasive species on the site which could colonize the LID practice?
Access, sequencing, staging, and constructability	Where will the contractor access the site? What is the ideal construction sequence, and where could materials and supplies be stored during construction? Do site characteristics constrain standard construction practices? Will it be a difficult job? Do constructability issues require a field change or amendment to the design or project tender?

Low Impact Development. A stormwater management strategy that seeks to mitigate the impacts of increased urban runoff and stormwater pollution by managing it as close to its source as possible. It comprises a set of site design approaches and small scale stormwater management practices that promote the use of natural systems for infiltration and evapotranspiration, and rainwater harvesting.

The portion of water precipitated onto a catchment area, which then flows as surface discharge from the catchment area past a specified point.

Water from rain, snow melt, or irrigation that flows over the land surface.

Soil, sand and minerals washed from land into water, usually after rain. They pile up in reservoirs, rivers and harbors, destroying fish-nesting areas and holes of water animals and cloud the water so that needed sunlight might not reach aquatic plans. Careless farming, mining and building activities will expose sediment materials, allowing them to be washed off the land after rainfalls.

Mineral particles which are smaller than 2 mm, and which are free of appreciable quantities of clay and silt. Coarse sand usually designates sand grains with particle size between 0.2 and 0.02 mm.