NOVEL USE OF AN AUTOMATED DYE INJECTION SYSTEM TO OBTAIN DISCHARGE VALUES OF A DYE TRACE IN WARD BRANCH WATERSHED, SPRINGFIELD, MISSOURI

Dye tracing of watersheds is one way to assess the interaction between surface and groundwater. The Ward Branch Watershed located in the southern quadrant of Springfield in southwest Missouri, Greene County contains both surface water and an intricate groundwater system full of recharge and discharge areas. The intricacy of the groundwater system is due to the karst terrain of Southwest Missouri, characterized by Burlington Limestone, gaining and losing streams, and numerous sinkholes where the surface water flows into the groundwater system. A dye trace was conducted to analyze the interaction of one specific recharge and discharge area within the watershed. The trace was used to observe the discharge at two springs with a steady-state injection of Rhodamine WT dye into a recharge site. This steady-state injection was achieved by a pump that maintained 3.6 milliliters of Rhodamine WT per minute into the sinkhole recharge site. The constant injection methodology used in this study has not been reported in at least a decade of dye tracing in this area. The numerous sinkholes being discovered in the Ward Branch area are located around major roads and where new development is still occurring. The discharge rates and concentrations of dye calculated from this trace will assist future mapping of the recharge area for each spring. The completion of this mapping will help foster more efficient urban planning. The data can also be used to find sources of contamination of the Ward Branch watershed and possible locations where channels of cave systems connect.