Analyze the job site topography

• Check the off-site drainage pattern. Where is water coming onto the site? Where is water leaving the site?
• Check the on-site topography for surface runoff, puddling and percolation.
• Determine the on-site runoff pattern; high points, ridges, valleys, streams, and swales. Where is the water going?
• Overlay the grading plan and indicate watershed areas; calculate square footage (acreage), points of concentration, low points, etc.
• Check the means of discharge (to comply with local codes and National Pollution Discharge Elimination System stormwater regulations).
• On-site (pond, creek, retention basin, dry wells)
• Off-site (street, storm drains)
• Natural drainage system (swales)
• Existing drainage system (drain pipe)
• Proposed drainage system

Analyze the other site conditions

• Land use and physical obstructions: walks, drives, parking, patios, landscape edging, fencing, grassed area, landscaped area, tree roots
• Soil type, to determine water absorption
• Vegetative cover, to determine the amount of slope possible without erosion

Analyze areas for probable location of drainage devices

• Identify what type and size drains are required; be sure to account for anticipated peak flow volumes.
• Design the system using a combination of surface and subsurface drain systems and underground pipes.
• Design pipe layout to convey water from the drains to the dry well or discharge point in the most direct and simple manner possible.