Riparian Areas are defined as:
“Vegetated ecosystems along a waterbody through which energy, materials, and water pass. Riparian areas characteristically have a high water table and are subject to periodic flooding and influence from the adjacent waterbody. These systems encompass wetlands, uplands, or some combination of these two land forms. They will not in all cases have all of the characteristics necessary for them to be classified as wetlands.” (Management Measures for Wetlands - I. Introduction, E1).

Vegetated treatment systems (VTS) are defined as vegetated filter strips:
“Created areas of vegetation designed to remove sediment and other pollutants from surface water runoff by filtration, deposition, infiltration, adsorption, absorption, decomposition, and volatilization. A vegetated filter strip is an area that maintains soil aeration as opposed to a wetland that, at times, exhibits anaerobic soil conditions”, and constructed wetlands:
“ Engineered systems designed to simulate natural wetlands to exploit the water purification functional value for human use and benefits. Constructed wetlands consist of former upland environments that have been modified to create poorly drained soils and wetlands flora and fauna for the primary purpose of contaminant or pollutant removal from wastewaters or runoff. Constructed wetlands are essentially wastewater treatment systems and are designed and operated as such though many systems do support other functional values.” (Management Measures for Wetlands - I. Introduction, E3)

Wetlands and riparian areas serve an important function in the reduction of nonpoint source pollution because they serve as filters for surface runoff, subsurface flow, and ground-water flows, thereby buffering or preventing the entry of pollutants into receiving waters. The vegetation in wetlands can prevent or reduce erosion and sedimentation. Vegetated treatment systems can perform some of the same functions as wetlands and riparian systems, such as preventing or trapping the entry of sediment, sediment-bound pollutants, and nutrients into waterbodies.

Activities that can affect the ability of wetlands or riparian areas to filter nonpoint source pollutants include: the drainage of wetlands to increase cropland, overgrazing, highway construction, channel modification, the deposit of dredged material, and port and marina excavation. Thus, this nonpoint source category overlaps and is interconnected with the other nonpoint source categories.

The EPA has identified three management measures to address this nonpoint source category:

1.Protection of Wetlands and Riparian Areas;
2.Restoration of Wetlands and Riparian Areas; and
3.Promoting the Use of Vegetated Treatment Systems, such as Constructed Wetlands and Vegetated Filter Strips.

For more information on these management measures, please refer Chapter 7: Management Measures for Wetlands, Riparian Areas, and Vegetated Treatment Systems of the EPA’s Guidance Specifying Management Measures for Sources of Nonpoint Pollution in Coastal Waters.

How This Source Category Applies to Alaska
In Alaska, wetlands make up approximately 65% of the state’s land area and include bogs, muskegs, wet and moist tundra, ferns, marshes, swamps, mud flats, and salt marshes. Development of Alaska’s wetland areas has been very limited compared to the Lower 48 states. In 1995, it was estimated that cumulative long-term losses were less than 1/10 of 1 percent of Alaska’s total wetlands. Most of the state’s wetland loss has been due to agricultural development, to construction of the North Slope oil facilities and haul road, and to development in the Anchorage and Juneau areas before the wetland management plans for these municipalities were adopted.

Local ordinances relating to management measures for wetlands, riparian areas and vegetated treatment systems:
The local ordinances in Alaska that relate to management measures for wetlands, riparian area and vegetated treatment systems are linked to the following table. The ordinances are grouped by the management measure they relate to (management measures 53 through 55, below).

Each ordinance is identified by municipality, ordinance title and reference number. Many Alaskan municipalities have codes of ordinances which are available online. Whenever possible, a direct link is provided to the local ordinance online. Otherwise, the ordinance text is available in PDF (Adobe Acrobat) format. A free copy of the application required to view and print PDF files can be downloaded at Adobe Acrobat Reader.