The square grid technique was used for assessing water resource potential aswell as for planning hydrometric networks and can be extended to generatedsynthetic streamflow on ungauged streams. The technique was developedinitially for obtaining co-ordinated maps of precipitation, evaporation andrunoff on a long-term mean annual basis and was extended to the estimation ofthe same hydrological elements on a monthly basis. This report presents theapplication of the square grid technique to the estimation of mean monthlyrunoff in a pilot area in Nova Scotia, chosen as the location of a proposedgas pipe line in anticipation of future data needs for ungauged locationsalong the proposed route. The model is calibrated for 8 hydrometric basinswithin the study area and verified and assessed on 3 gauged basins.

A system was developed to simulate the overland flow of rainfall runoff in a microgeometric model of the landscape. The landscape model was developed from normally available materials by means of a geographic data-handling system. The water flow model provides both direct rainfall and grid-to-grid flo components for every grid on the landscape. The size of the grid, the time increment for analysis, and the rainfall intensity are adjustable by the user. The surface flow is followed in an eight-nearest-neighbor microflow pattern across the landspace until the flow reaches channels within the grids. The system provides flow patterns within the watershed, effective drainage area and runoff curve numbers for every grid, and a complete flow time history for each grid. The system was developed according to an objective mathematical approaches so that it does not require extensive technical knowledge for operation; it was designed to use normally available data at reduced computer operation cost . This previously unavailable technical procedure is expected to be useful in erosion studies and as an aid in U.S. Army Corps of Engineers construction activities. Military applications include an ability to rapidly assess, for anticipated rainfall conditions, areas with potential cross-country mobility problems induced by storm runoff.