The State of Kansas, under the Clean Water Act of the United States, is establishing Total Maximum Daily Loads (TMDL) on all stream segments with designated uses to provide a quantitative basis for water-quality assessment. Chloride is one of the substances considered as a pollutant in the TMDL process. A key element of the Clean Water Act is the restoration of waters. Although there are chloride contributions from anthropogenic sources, the main chloride input to the waters of Kansas is from natural geologic sources. The former state of some of the streams and wetlands of Kansas before settlement was saline. Therefore, any restoration of Kansas streams must consider the natural conditions contributing chloride. The Kansas Department of Health and Environment (KDHE) requested the Kansas Geological Survey (KGS) apply knowledge concerning natural sources and procedures for differentiating salinity sources to assist in the process of developing TMDL's for chloride. The focus of this report is on the Arkansas River in the Gar-Peace Subbasin and the Cow Creek Subbasin where stream segments are listed by the KDHE as impaired by chloride with a high implementation priority.