[en] One new Resource Conservation and Recovery Act (RCRA) groundwater monitoring well was installed at the 216-S-10 pond and ditch during November and December 1999 in fulfillment of Tri-Party Agreement (Ecology 1996) milestone M-24-42. The well is 299-W26-13 and is located at the northeast comer to the 216-S-10 pond, southwest of 200 West Area. The well is a new downgradient well in the monitoring network. A figure shows the locations of all wells in the 216-S-10 pond and ditch monitoring network. The new well was constructed to the specifications and requirements described in Washington Administrative Code (WAC) 173-160 and WAC 173-303, the groundwater monitoring plan for the 216-S-10 pond and ditch (Airhart et al. 1990), and the description of work for well drilling and installation. During drilling and construction of well 299-W26-13, sampling and analysis activities were done to support remedial action, closure decisions at treatment, storage and disposal facilities, and to confirm preliminary site conceptual models developed in the 200-CS-1 Work Plan (DOE/RL 1999). This document compiles information on the drilling and construction, well development, pump installation, and sediment and groundwater testing applicable to well 299-W26-13. Appendix A contains the Well Summary Sheet (as-built diagram), the Well Construction Summary Report, and the geologist's log. Appendix B contains results of field and laboratory determinations of physical and chemical properties of sediment samples. Appendix C contains borehole geophysical logs. Additional documentation concerning well construction is on file with Bechtel Hanford, Inc., Richland, Washington