We all know that stormwater runoff carries trash and debris into our water ways, but have you ever wondered what kind of material this runoff picks up?A Contech Continuous Deflective Separation unit (CDS) was installed on a site in California and the performance of the unit was monitored over a 12 months. During a maintenance event, the trash and

At about 2.5% of the total water volume on the planet, we’ve always had roughly the same amount of freshwater.  Unfortunately, it seems that, at the local level, the amount of fresh water made available through precipitation is increasingly erratic, with the last year featuring historic floods in the eastern US and historic drought in the west.  In

Stormwater infiltration is defined as the process by which water enters the soil and recharges streams, lakes, rivers, and underground aquifers. Stormwater infiltration is a fundamental component of the water cycle and is quickly becoming the centerpiece of stormwater management strategies across the United States.  Stormwater infiltration is an

Most models and approaches toward cost accounting of Stormwater Control Measures (SCMs) use standardized engineering economics. These models use the first cost and annualized O&M costs, brought forward to present value using assumed interest rates, etc.  Models that are more sophisticated will break the first costs down to show engineering design,

Bioretention and green roofs have become the centerpieces of Low Impact Development (LID) initiatives throughout North America. The well-publicized benefits of these two types of stormwater management practices focus on runoff reduction, stormwater quality treatment, and landscape aesthetics. Promotional literature provided by various regulatory

System hydraulics refers to how water flows through a stormwater filtration system. The following three steps should be part of the hydraulics evaluation process.1. Evaluate the hydraulic grade line (HGL) at the design flow rate. Typically, a backwater calculation from the point of downstream control should be performed to ensure the system can

Perhaps the most recognized Low Impact Development technique, bioretention, incorporates landscaped features to slowly percolate stormwater runoff through plants and engineered soil prior to infiltrating that water into native soils. Where feasible, these systems can be a low cost, high efficiency stormwater management practice that can also

During the past decade, a number of different media have been used for stormwater filtration and more recently for bioretention.  Media such as sand, peat, and compost have been used successfully.  Uses of perlite, zeolite, carbon, and other "exotic" media have expanded the choices for targeting specific pollutants.   Media are now being used to

Since the Environmental Protection Agency, and in turn state and local regulators, have gone all in on green infrastructure (GI) and low impact development (LID) concepts a seemingly regrettable consequence has emerged.  Topics specific to the broader adoption and implementation of GI have monopolized our collective dialog on stormwater management

All stormwater systems need to be maintained to continue operating effectively, and rainwater harvesting (RWH) is no exception. Unfortunately, many owners do not care that their stormwater BMP is not functioning due to lack of maintenance. Maintenance of RWS systems is critical for owners that depend on their continued operation and associated