Stormwater FAQ

Stormwater 101

What is stormwater?

Stormwater is water on land surfaces that originates from precipitation. It is a natural and important part of the hydrologic cycle. Some precipitation soaks into the ground and becomes part of the soil moisture. Most of it runs over land and arroyos or through streets, channels and drains.

A watershed is a land surface that produces stormwater runoff during precipitation. The flow accelerates as it drops in elevation, and increasing amounts of debris are carried by the stream. A large amount of precipitation in a small watershed produces a destructive stream of stormwater runoff. The combination of speed plus debris increases the destructive force of the flows.

Flooding occurs when stormwater runoff exceeds the capacity of an arroyo or channel. Adverse impacts include dislocation, property damage and loss of life. Damage from runoff can be curtailed by implementing the following:

  • land use development controls and open space planning
  • erosion controls that limit the amount of rocks and
  • debris washed away with the runoff
  • structural flood control systems
  • stormwater systems

What are stormwater systems?

A stormwater system is designed to minimize flooding. It collects stormwater runoff, dissipates energy (reduces speed of flowing water), removes debris, and safely channels the flow to a designated collection point or receiving stream. El Paso's stormwater system includes man-made and natural features.


How do arroyos and open space provide natural stormwater management?

Natural arroyos provide a stormwater runoff conveyance with built in energy dissipation and debris removal features. Some arroyos are protected from development and remain as natural channels. Natural depressions can also be used to retain stormwater runoff. These areas can be integrated into the stormwater system while being preserved as wilderness areas.


How do park ponds help?

Detention ponds are a key part of the stormwater system. They retain water, dissipate energy, percolate stormwater into aquifers and remove debris. Historically, ponds were narrow, deep and fenced to keep people out.

Recently, they have been made wide and shallow, so grass, trees and other park features can be incorporated. More detention ponds will be constructed as park ponds. This allows them to retain their stormwater function and increases the number of city parks.


The Stormwater system

What facilities comprise the stormwater system?

El Paso's stormwater system has the following major components:

  • pump stations – 21
  • ponds – 310 (904 acres)
  • dams and basins – 39 (2,430 acres)
  • channels – 74 miles
  • agricultural drains – 42.7 miles
  • storm drain conduits – 145.6 miles
  • storm drain drop inlets – 6,094

What is the difference between a storm drain and a sewer?

Sewer pipes capture used water and liquid waste from homes and businesses and carry it to wastewater plants for treatment. Treated wastewater can be reused for landscape irrigation, industrial and construction purposes. It also helps sustain the aquatic habitat of the Rio Bosque wetlands and provides water for farming in the Mission Valley.

Storm drains are separate from the sewer system and, unlike wastewater, stormwater is not treated and reused. Storm drains carry runoff to the Rio Grande and retention basins. Some storm drains are under streets, but much of the system consists of open canals, street gutters and other features that collect, channel and divert stormwater runoff.


System management

Why does El Paso have a stormwater utility?

In 2006, a major storm caused city-wide flooding when El Paso received a year's worth of rain in two days. The storm caused more than $200 million in damages to businesses and homes and $115 million in damage to the city's stormwater system. Stormwater improvements had been deferred because of a lack of dedicated funding, and many facilities were undersized or in need of maintenance. In response to this problem, the City Council established a stormwater utility that would be operated and maintained by El Paso Water and supported by monthly user fees.

Why was EPWater selected to oversee system operations and maintenance?

EPWater has expertise in managing the region's water resources and the city's water, wastewater and reclaimed water systems. It also has a proven track record in financial management, which is evidenced by its superior bond rating. EPWater has received national and international recognition for excellence in operations and management, while maintaining rates that are among the lowest in the state.

What is involved in managing El Paso's stormwater drainage?

Stormwater utility functions range from operating and maintaining the stormwater system to generating revenues through rates. Stormwater crews remove vegetation, trash, debris and silt from facilities to keep the stormwater flowing. They also repair and maintain the infrastructure and provide sandbags for flood control.

What is a stormwater master plan?

Stormwater master planning and a long-term capital improvement plan are key elements when managing stormwater drainage. The stormwater master plan outlines a long-term program to reduce the flood risk to residents and their property by improving the drainage infrastructure. The master plan identifies deficiencies in the stormwater system and develops alternatives for addressing them. It also recommends system improvements and the priority for implementing the projects.

How was El Paso's master plan developed?

An engineering firm hired by the Public Service Board identified and prioritized all stormwater capital projects that would be proceeding into design and construction over the next 10 years and beyond. Public participation was a big part of the planning process.

What does the master plan accomplish?

The master plan addresses long-standing stormwater system deficiencies that routinely cause flooding in some areas of the city, even with very little rainfall. The plan focuses on major threats, which is a cost-effective method of addressing flood and drainage problems. Nearly 100 capital projects are identified at an estimated cost of $650 million. These improvements are the basis for significant reductions in flood risk, economic, transportation and safety issues.

What happens when severe rains hit before projects are completed?

Many maintenance problems have been addressed and many capital improvement projects have been completed. The stormwater system functions more effectively and flooding has been reduced in many sections of the city.

Community benefits

How does the stormwater utility benefit El Paso?

Stormwater fees fund system maintenance and construction projects, and residents are better protected in both the short and long term. Areas that historically flooded were evaluated, and solutions are being pursued. The system also benefits from increased maintenance. Preventive maintenance continues to be a priority, and crews work throughout the year to keep the system clean. Maintenance reduces flood risk by reducing blockages and overflows.

How will the stormwater utility protect arroyos and open space?

Ten percent of annual stormwater fee revenue is used for projects that preserve open space and greenways while channeling or retaining stormwater runoff. The funds set aside for green projects also help fund park pond projects.

Fees and rate structure

Who pays stormwater fees?

Stormwater fees are assessed for property owned by organizations, El Paso County and city government and El Paso Water, as well as commercial, industrial and residential properties. Federal and state agencies, public institutions of higher education, the Housing Authority of the City of El Paso and independent school districts are exempt, as well as undeveloped lots and agricultural land. Churches and nonprofit social service agencies are billed at a reduced rate.

How are stormwater fees used?

The fees are used only for stormwater utility expenses. They fund system operations, maintenance and capital improvement projects, as well as open space and green projects. Fees are based on the amount of impervious surface areas.

What is an impervious surface?

Impervious surfaces includes any nonporous area that has been disturbed from its natural condition in a way that reduces the ability of the surface to absorb water into the soil. Examples are compacted soils, buildings, pavement, parking lots, driveways, sidewalks and other man-made structures or surfaces built or laid on the natural surface of the land that alter stormwater runoff so that flows are increased. For billing purposes, turf, xeriscaped areas, driveways, walkways and sidewalks are not included.

How is the amount of impervious area calculated?

The impervious area of properties is determined by using aerial photographs and information in EPWater's Geographic Information System, along with El Paso Central Appraisal District real property Information.

For residential property, impervious area refers to the ground floor of the house, garages, porches, patios, and any additional buildings, storage sheds or other areas that cannot be penetrated by rain; however, driveways, sidewalks, turf and xeriscaped areas are not included in the calculation.

Is the stormwater fee affected by the amount of rain?

No. The stormwater fee funds ongoing maintenance and improvements to the drainage infrastructure. These items are not affected by the amount of rain.

Does the money collected for water service fund stormwater needs?

No. The stormwater utility is a stand-alone, self-sufficient utility. Water and wastewater revenue, which is accounted for separately, is not used to fund stormwater needs.

Should stormwater improvements be financed through bonds to ensure that funds are spent for their intended purposes?

All stormwater fees are used to improve and maintain the stormwater system; however, some projects will be financed from outside sources such as bonds.

Why are fees assessed to properties that don't contribute to runoff?

As with all public infrastructure, the stormwater system benefits all residents because they all travel on El Paso's streets and highways and benefit from stormwater control. Therefore, all residents pay to improve and maintain the system; however, credits are available for properties with onsite ponds that capture and retain stormwater.

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