From September 2019 to October 2020 a stream sediment budget and sediment fingerprinting integrated study was conducted to quantify upland and stream corridor sources of suspended sediment and sediment-bound phosphorus using the Sediment Source Assessment Tool (SedSAT) methods with a suite of trace elements. Upland source samples were collected at 45 randomly selected sites in the watershed. Passive suspended-sediment samplers were installed at three sites and sampled monthly. Soft, fine-grained streambed sediment was collected if present at 18 rapid geomorphic assessment (RGA) sites. An inventory of bank erosion and soft-sediment deposition was also done at each of the 18 RGA sites, which were selected to represent a range of stream sizes and geomorphic conditions. This data release includes field-collected data from RGAs, trace elements laboratory results, and sediment budget calculations for the Kinnickinnic River basin, Waukesha County, Wisconsin.