The Hemlock Pond Pothole has an interesting and colorful history that extends back into the earlier portions of the last century. Earliest information is that the area was used as a rhubarb farm and other agricultural applications. The land did endure periods of inundation during the seasonal wet periods. Records indicated that the section corner stone was difficult to set, because of high ground water. In the 1920?s the local farmers constructed a ditch that drained the area north into what is now known as Tip-top Pothole.
In the 1940?s this ditch was improved and a portion of it piped through the Hopp property. These improvements resulted in a series of lawsuits from the down stream property owners who operated a dairy farm on the north side of 136th St. The dairy farms contention was that the diversion of the flow from the hemlock pothole to the tip-top pothole damaged their hay production and wanted to be compensated. The result of this action was that the conveyance was closed.
In the 1970?s the Rosehill horse farm located on the eastern edge of the pothole started to have increased flooding problems. These problems persisted into the 1980?s when through the result of a lawsuit. Pierce County raised 144th St. E. and constructed a berm with a control structure to protect the adjacent property. In the 1990?s the Horse farm was converted into subdivision with and infiltration system for storm water control. The flaws in this system started a series of events when private citizens altered the control structure with in the berm to best protect their own interests.
In 1996 one of the larges storm events in recent history occurred and cause extensive flooding in the south hill plateau area. The result of this flooding provided the incentive for Pierce County to construct the current pump station. The permit process for this construction included a wetland component that set a minimum elevation for the adjacent wetland known as Hemlock pond.
