What is exfiltration trench?

The subsurface exfiltration trench is a stormwater management practice that is commonly used in south Florida. Exfiltration trenches in south Florida are usually constructed near or beneath the water table to induce artificial recharge (exfiltration) of stormwater.

What is an exfiltration pipe?

Exfiltration is leakage from a watertight pipe system into the surrounding soil, and potentially, the water table. The US Environmental Protection Agency states that, “a combination of relatively low groundwater table and shallow sewer creates the potential for widespread exfiltration.”

What is exfiltration in stormwater?

In general, exfiltration is an engineering term used to describe the movement of. stormwater out of a designed water management system. Systems that allow. Stormwater to exfiltrate include perforated pipes and underground chambers. Exfiltration systems can also include pervious pavements that allow stormwater to move.

How does an infiltration trench work?

An infiltration trench is a long, narrow, shallow excavation located over porous soils and back-filled with stone to form a subsurface reservoir to hold stormwater and allow it to infiltrate the soil. The sheet flow enters the trench through a layer of vegetated porous soil on the top of the trench.

What is infiltration and exfiltration in sewer pipe?

Exfiltration is the leakage of wastewater out of a sanitary sewer system through broken or damaged pipes and manholes. Exfiltration is a big problem facing water and wastewater infrastructure. Its effects can harm public health and the environment and necessitate costly repairs.

What is the difference infiltration and exfiltration?

Air infiltration is the movement of air into a building, whereas air exfiltration is the movement of air out of a building. Air flows into or out of a building because of pressure differences between the internal and external environments of the building.

What is the difference between inflow and infiltration?

Infiltration occurs when groundwater seeps into sewer pipes through cracks, leaky pipe joints and/or deteriorated manholes. Inflow is stormwater that enters the sewer system through rain leaders, basement sump pumps or foundation drains illegally connected to the sewer.

How are exfiltration trenches different from infiltration trenches?

Exfiltration trenches Exfiltration trenches are similar to infiltration trenches but differ primarily in the the manner in which stormwater is delivered to the trench. Runoff enters infiltration trenches directly by infiltration from the surface.

What kind of stone should be used in an infiltration trench?

For advice on decorative surface aggregates see Stone Gravel used for underdrains in bioretention, infiltration trenches and chambers, and exfiltration trenches should be 20 or 50 mm, uniformly-graded, clean (maximum wash loss of 0.5%), crushed angular stone that has a porosity of 0.4 .

Why is geotextile used in infiltration trenches?

Trench laid in advance of the surrounding catchment being finished. This system would benefit from some geotextile on the surface to prevent sediment from accumulating before the asphalt is laid. Good use of geotextile, being limited to preventing fines from entering the trench from above.

How big is an infiltration trench in Virginia?

In function though, the decorative surface course of the infiltration trench needs to remain free-draining down into the trench, whereas the gravel diaphragm is designed to spill over onto adjacent land, leaving sediment behind in the gravel or stone channel. Virginia up to 10′ (3 m) deep.