Construction specifications for Infiltration basin

CADD based details for pond systems are contained in the section on drawings. The following details, with specifications, have been created for infiltration systems:

• infiltration basin
• infiltration trench
• subsurface infiltration system
• inlet/outlet structures

Construction specifications

Given that the construction of infiltration practices incorporates techniques or steps which may be considered non-standard, it is RECOMMENDED that the construction specifications include the following format and information.

Temporary erosion control

• Installation prior to site disturbance
• Catch basin/inlet protection
• Use of BMP as temporary sedimentation basin

Excavation, backfill and grading

• Timing of grading of infiltration practices (relative to total site development)
• Use of low-impact, earth moving equipment
• Controls to ensure site is not over-excavated
• Restoration in the event of sediment accumulation during construction of practice
• Gravel backfill specifications
• Gravel filter specifications
• Filter fabric specifications
• Observation well specifications

Native plants, planting and transplanting

• Site preparation of planting areas
• Timing of native seeding and native planting
• Weed control
• Watering of plant material

Warning: It is REQUIRED that infiltration systems not be excavated to final grade until the contributing drainage area has been constructed and fully stabilized.

Construction sequence scheduling

• Temporary construction access
• Location of silt fence installation to protect BMPs and downgradient receiving waters
• Removal and storage of excavated material
• Installation of underground utilities
• Rough grading
• Seeding and mulching disturbed areas
• Road construction
• Final grading
• Site stabilization
• Installation of semi-permanent and permanent erosion control measures
• Silt fence removal (often forgotten but an essential step)

Construction observation

• Adherence to construction documents
• Verification of physical site conditions
• Erosion control measures installed appropriately

Related pages

• Overview for Infiltration basin
• Design criteria for Infiltration basin
• Construction specifications for Infiltration basin
• Operation and maintenance of Infiltration basin
• Cost-benefit considerations for Infiltration basin
• External resources for Infiltration basin
• References for Infiltration trench