, March 20, 2008 (ENS) - A total of 57 lakes and 111 different streams or stream segments in South Dakota are impaired and have been targeted by state water officials for total maximum daily load, TMDL, development, according to the latest draft report on surface water quality.
To identify impaired waterbodies in the state, the South Dakota Department of Environment and Natural Resources, DENR, is finalizing a draft 2008 Integrated Report for Surface Water Quality Assessment. The final report must be submitted to the U.S. Environmental Protection Agency by April 1, 2008.
This document combines the 305(b) report and 303(d) list into one Integrated Report, which provides an assessment of the quality of South Dakota's surface water resources and identifies the impaired waterbodies that need TMDLs.
According to the draft report, South Dakota has about 9,289 miles of perennial rivers and streams and about 85,841 miles of intermittent streams.
About 7,904 perennial stream miles have been assessed in the past five years - October 2002 to September 2007.
During this timeframe, 49 percent of assessed stream miles were found to support all assigned beneficial uses and 51 percent were nonsupporting of their designated uses.
Seventy-seven percent of stream miles designated for immersion recreation supported that beneficial use; 23 percent did not meet the criteria.
A total of 111 streams or stream segments are listed as impaired and require TMDL development.
Similar to previous reporting periods, nonsupport for fishery/aquatic life uses in streams was caused primarily by total suspended solids from agricultural nonpoint sources and natural origin.
Nonsupport for recreational uses was primarily caused by fecal coliform contamination from livestock.
In addition to rivers and streams, South Dakota has 570 lakes and reservoirs with specific aquatic life and recreational beneficial use classifications. The four Missouri River mainstem reservoirs were not included in the total lake acres but were included in the monitored river mileage.
An estimated 124 of the 570 classified lakes have been assessed. Eighteen lakes assessed during the 2006 reporting cycle did not have sufficient data to determine support status during this reporting cycle. The assessed lakes account for 65 percent of the total classified lake acreage.
An estimated 49 percent of the assessed lake acreage was considered to support all assessed beneficial uses and 51 percent did not support assessed beneficial uses.
A total of 57 lakes are listed as impaired and require TMDL development.
Sediment and nutrients conveyed in surface water runoff are the main nonpoint source pollutants impacting South Dakota lakes and reservoirs.
The DENR continues to conduct special chemical/physical/biological stream surveys and ambient monitoring to assess the quality of receiving streams and to document water quality problem sources and improvements.
It is the intent of this report to inform the citizens of South Dakota and the U.S. EPA of the condition of state surface water resources and it will serve as the basis for management decisions by government and other entities for the protection of surface water quality.
DENR also will use the Integrated Report as a tool to continue to stimulate development of nonpoint source projects and to produce a priority waterbody list for the department.
This report is shared with the Nonpoint Source Task Force to help focus its efforts and provide information used in the priority waterbody ranking system.
Public comments on the draft report were accepted during a public notice period that ended today.
The Integrated Report will be available to all state conservation districts and water development districts. Each district can review watershed information for its geographical area of interest. This helps the districts focus on the location, nature, and severity of surface water problems in their areas. This generally leads to public discussions, which start the long process toward nonpoint source pollution control implementation.
Copyright Environment News Service (ENS) 2008. All rights reserved.
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