Over the past century, runaway development has paved over forests, fields and wetlands across the country. Along with urbanization has come the problem of "urban stormwater" – rainwater that washes over dirty surfaces such as roads, buildings and lawns and becomes a major source of pollution in rivers, lakes and bays. While much has been achieved in the past 30 years to limit pollution from easily identifiable sources, such as watersheds, efforts to control pollution from these diffuse sources are still in their infancy. Although the Clean Water Act mandates stormwater control, local governments have been slow to respond.
This report, however, focuses on runoff pollution from developed areas, which occurs when stormwater carries away a wide variety of contaminants as it runs across rooftops, roads, parking lots, baseball diamonds, construction sites, golf courses , lawns, and other surfaces in our cities and suburbs. The oily sheen on rainwater in roadside gutters is but one common example of urban runoff pollution.
Nationwide, sediment is a leading pollutant of our waterways.
Rainwater that washes over roads, buildings and lawns carries pollution into oceans, rivers and lakes. Impervious surfaces increased 41 percent during the 1990s compared to an 8–percent increase in population. The rate of increase of impervious surface implies there will be more rapid delivery of nutrients to streams and an increase in sediment erosion.
Recovery of the Chesapeake Bay Federal rules force constructors and contractors disturbing an acre or more of land during any type of construction project to develop a plan for preventing erosion and controlling sediment at the construction site.
One solution is to use porous materials and systems that allow stormwater to be filtered by the soil. Instead of solid materials, paving can be designed to allow water to flow through into the soil. Catch basins for stormwater are now recognized as an effective method to minimize pollution. One suggestion is to direct residential drain pipes to empty into the yard rather than a ditch. Individuals can help limit pollution by being careful with fertilizers and chemicals.
Stormwater runoff and non–point source pollution are the number one threat to water quality. Stormwater pollutes sensitive trout streams with sediment, pesticides, fertilizers, and causes erosion, flooding, and loss of habitat.
"Storm water can be controlled at its source" by "something as simple as planting trees," using more sensible tree pit design and installing green roofs that collect storm water. Storm water can also be naturally absorbed through vegetation, green areas and impervious surfaces, the
councilman said. "But, it's what's underneath the ground – a natural filtration system – that really makes the bioretention systems work. The vegetation and soils remove pollutants from the stormwater, such as nutrients, suspended solids, salt, and petroleum byproducts. The goal is to reduce flooding by slowing the flow and to have cleaner stormwater throughout the James Brook/Jacob's Meadow watershed, which flows directly into the
harbor"
Development on forested steep slopes causes massive erosion, sedimentation of streams and wetlands, downstream flooding,and destruction of prime habita.
Landowners with property along streams, wetlands and moist bottomlands are encouraged to protect these riparian areas by planting trees that will create buffer zones, prevent soil erosion and attract wildlife.
Citizens can make a difference by removing from their private property invasive plant species that contribute to poor water filtering and soil erosion, and planting native trees and shrubbery that increase absorption of rainwater and improve water filtering efficiency.
By adopting 'green infrastructure' solutions, such as green roofs, permeable pavement, wetland restoration, and smarter design of street tree plantings, stormwater can be captured where it falls and used to green the city. It introduces benchmark environmental indicators as well as
80 specific measures, to capture hard data which will be used to build up a clear picture of trends and pressures over time.
The problem extends beyond neighborhood water runoff. Fertilizer runoff into the Mississippi River is blamed for the dead zone that occurs in the Gulf of Mexico. The same problem occurs from residential areas where lawn fertilizer finds its way into the waterways. Additionally, chemicals, human and animal waste wash into our water systems.
The Conservation Reserve Enhancement Program (CREP) is a voluntary land retirement program that helps farmers and other agricultural producers protect environmentally sensitive land, decrease erosion, restore wildlife habitat, and safeguard ground and surface water.
Contaminated runoff from freeways is the largest and most polluted part of overall stormwater runoff.
Caltrans will start cleaning up the runoff using a variety of innovative solutions to capture the mess before it reaches the beach.
Cleanup options include sand traps, catch basins and new porous pavement surfaces that catch polluted runoff and absorb the contaminants.
Polluted runoff is the number one water pollution problem in America, Caltrans deserves credit for blazing a pathway that other agencies and cities should now follow.
Action is well overdue to address our deteriorating water quality. This website clearly identifies the decline in water quality in areas dominated by agricultural and urban land use, and offers solutions to these troubling trends. Both agriculture and local bodies must add more action to their rhetoric. It will be sad if agriculture uses urban water quality results as pretext for inaction. While the median bacteria count in urban streams is higher than the median count on rural steams, the worst rural waterways are far, far worse than the worst urban stream.
