“Low Investment, Low Impact Sustainable Water Management Techniques” by Gale’s John M. Perry, P.E. was published in the Facility Management Journal.
Most state regulated stormwater standards mandate that Low Impact Development (LID) techniques be considered when planning drainage solutions. In some cases owners and designers have seen this as burdensome, unnecessary or over the top. What many owners are not aware of are the significant potential cost savings associated with LID techniques. Consider a road or access drive with a traditional curbing and closed drainage conveyance system. The road will have curbing on both sides, two catch basins and one drain manhole per every 300 feet and a minimum 12-inch drainge pipe along the entire length. Now consider the same roadway with a vegetated conveyance swale on each side; this will have no curbing, no drainage structures and no piping. An owner can expect to pay up to $155 per linear foot for the traditional closed drainage system versus around $58 per linear foot for the vegetated swale option; a savings of almost 3 times. Other cost savings measures of LID techniques are:
- Use bioretention as landscape area to meet zoning requirements – two for one deal.
- Bioretention areas negates the need for multiple catch basins within a parking lots, typically only one catch basin is needed as an overflow.
- Bioretention areas can eliminate or greatly minimizes the need for underground storage which can result in large savings in plastic or concrete chambers and crushed stone.
- The use of permeable surfaces for recharge can be used for in place of infiltration basins which can lead to more space for development and potential revenue.
- Proper site selection can minimize disturbance to wetlands and habitats therefore reducing costs of mitigation efforts. Proper site selection can also limit dewatering efforts, costly erosion control measures and overall site construction complexity.
- Use native plantings, they tend to be locally grown which limits travel and fuel costs.
- Drought tolerant plantings eliminate the need for irrigation thus saving on installation costs and water usage.
- Consider using silt socks rather than hay bales; they are easier to install / remove and can save significant labor.
- If work within wetlands is necessary, consider using directional drilling. You can save time and money on trenching, tree cutting, mitigation, replication, erosion control and permitting.
- Consider the use of LED site lighting. LED lighting gives flexibility to dim, put on timers and even control from your smart phone. You will pay a premium up front but can experience considerable savings in energy and fixture replacement over time.