Underground Exfiltration Trench Systems: How They Compare to Central Florida Agencies
Exfiltration Systems: Why They Work
Civil Engineers Typically calculate stormwater retention ponds to meet the requirements of your land development project. However, any rainwater pond it will commonly take more than 10% to 20% of the total available land area. The particular size of these storage water management basins is largely based on the types of soils found on the site; all other factors are equal. The land you use cannot be used for vehicle parking or for building construction. In this short article, I will summarize the exfiltration ditch requirements of the City of Orlando, Orange County, Seminole County, and the City of Sanford.
Provide greater use of land area
In order to allow greater use of the land for its intended use, “exfiltration trenches”, or underground vaults could possibly be used. Groundwater stormwater management systems are a viable method of managing project stormwater management needs, especially where land availability is limited. The use of an underground system for the management of rainwater allows the use of the upper area for parking lots and buildings. This allows the same area to be used for two complementary uses and increases project performance.
Exfiltration trenches are created from drainage pipes with small holes along their entire length. Underground vaults, by contrast, are manufactured from concrete structures with a large open area below and open at the bottom. Both systems provide a support surface for traffic and vehicle parking.
To create the necessary volume, the exfiltration trenches are made up of perforated drainage pipe located within a sculpted bed. This provides both a means to filter the volume of stormwater into the ground and a structural support for the upper pavement.
How regulations differ from one agency to another
orange county it’s pretty much the most developer-friendly agency within Central Florida, except when it comes to exfiltration trenches. Orange County will allow the use of exfiltration trenches, however the criteria for their use make them undesirable.
Section 30-281 (3) of the Orange County Land Development Regulations states: “in the event that exfiltration system fails, stormwater will be held at the site for the twenty-five year and twenty-four hour storm before stormwater is allowed to leave the site. ”
In essence, this requires the actual site to be designed as a bowl to ensure that the 8.6 inches of rain around the entire property is stored on site. This demand requires that the site become a container to store all this rain. This can allow approximately one foot to twenty-four inches of water on the property, especially on the parking lot in particular, as well as the landscaping areas. This is a very extreme requirement that makes the use of this excellent stormwater management strategy impractical and unlikely to be used. This is not shared by any of the nearby municipalities.
Tea Orlando city, Florida offers advantageous conditions regarding the use of exfiltration ditches for rainwater or underground vaults. The city’s engineering manual is currently being revised to allow civil engineers to design these systems with a factor of safety of 2. This is equivalent to the requirements of Seminole County, the City of Sanford, and the water management district. from the St. Johns River.
The particular exfiltration trench system requires cleanings at one end and manholes at the other. Cleanings and / or gutters should be spaced every three hundred feet for ease of maintenance. Civil engineers find that this strategy adheres to good engineering practice without being excessive.
Seminole County it also offers positive requirements regarding the use of underground exfiltration systems.
The Seminole Code Appendix B, Chapter 4.2 c. (4) states: “Filtration systems must be designed with a factor of safety of 2.0 (that is, the design uses half the permeability rate or half the reduction time).”
This criterion meets well Civil Engineering practical and conservative without having unnecessary negative consequences on the design of the underground exfiltration stormwater management system.
Tea City of Sanford Land development regulations include equally beneficial criteria regarding the use of underground exfiltration systems for stormwater management.
The Municipality’s Land Development Program O, Section 2.4 states: “It shall be designed with a safety factor of at least two … In addition, a sediment sink is required prior to the exfiltration trench system to capture sediment that they can clog pores in pipe and / or gravel.
The civil engineer designs this sediment sink to capture sediment in stormwater runoff that can clog pores within the pipeline or bedrock. The city’s strategy is similar to that of Seminole County and without undue burden.
The regional agency in charge of stormwater management systems is the St. Johns Water Management District (SJRWMD). The District has criteria related to trenching techniques that are actually very similar to those in Seminole County, the City of Orlando, and the City of Sanford. Orange County is the only municipality that discourages the use of these groundwater stormwater management strategies. Exfiltration ditch methods tend to be a good effective means of managing stormwater and can help increase the performance of your property. This allows for a more profitable stormwater solution that tends to increase your return on investment.
Higher yield from the land
Underground exfiltration The systems allow an additional effective increase in land area between 10% and 20%. Depending on the value of the land or its availability an underground exfiltration system it can be the difference between a viable project and one that is not.