Mean monthly runoff estimation at ungauged sites using the square grid technique

Abstract

The square grid technique has been used in the past for assessing water resource potential as well as for planning hydrometric networks. The method can be extended to generate synthetic streamflow on ungauged streams. The technique was developed initially for obtaining co-ordinated maps of precipitation, evaporation and runoff on a long-term mean annual basis. The technique was extended to the estimation of the same hydrological elements on a monthly basis (Solomon, 1984). This paper presents the application of the square grid technique to the estimation of mean monthly runoff in a pilot area in Nova Scotia. The pilot area chosen was the location of a proposed gas pipe line in anticipation of future data needs for ungauged locations along the proposed route. The square grid model is calibrated for eight hydrometric basins within the study area and verified and assessed on three gauged basins. This system can be used to store, process and retrieve information and may have numerous applications in the field of hydrology. The square grid computer program was purchased by the Water Resources Branch, Ottawa, and details needed to run the routines were not included. As part of this project it became necessary to expand on the consultant's documentation, hence, the section on "Program Input Files" is included in the main text.