This report presents the results of an investigation into the effects of floodwaterretarding structures in the 39 square miles of the Honey Creek basin above the stream-gaging station near McKinney, during the period October 1952 to September 1959. The number of such structures in the study area was increased from 2 to 12 during the investigation.
Data were collected which permit computation of basin and watershed precipitation, inflow to and outflow from each floodwater-retarding structure, evaporation and seepage from each pool, and a continuous record of discharge from the entire study area. Transpiration was not evaluated, but in the water-budget summary it is included in the item "pool consumption", together with evaporation and seepage.
During the 7-year study period, the annual inflow to the gaged pools ranged from 1.34 to 26.50 inches and averaged 7.39 inches, of which 0.73 inch was direct rainfall on the pool surface. The annual pool consumption ranged only from 1.33 to 1.85 inches, and averaged 1.62 inches. These results indicate that in a year of substantial runoff the floodwater-retarding structures would have only a minor effect on downstream water yield, but in a year of low runoff the structures would have a marked effect on downstream water yield.
The effect on the flood regimen at a downstream point because of floodwaterretarding structures in the headwaters will vary with the amount and intensity of the precipitation and with antecedent conditions. The beneficial effects of the structures on Honey Creek during the floods of April and May 1957 is illustrative. During the period April 19 to May 31, 1957, the total volume of inflow to the floodwater-retarding structures was equivalent to 4.3 times the combined capacities of the pools from an average basin rainfall of 30.31 inches. The retarding effects of the structures limited the flooding on Honey Creek at the gage to minor flooding on only five occasions during that period.
