Paddock scale topography and water flow paths; when this information is combined with the physiographic science, it provides a powerful tool demonstrating potential contaminant risk and transport across a landscape.
Farm Scale Hydrology
Most agricultural contaminants in waterways (such as sediment, phosphorus, and E. coli) are mobilised and enter the stream during rainfall events that result in overland flow (surficial runoff).
Understanding at a paddock scale how the water will move across the landscape during a rainfall event can help with strategic farm management decisions, as well as the placement of various mitigations or interventions. For example, by knowing where water will drain through a winter forage crop paddock, the grazing strategy can be managed accordingly leaving these high risk water convergence areas until last or avoided altogether (e.g. a planted buffer).
This assessment will also 'place' the property in the landscape, giving context to which streams, rivers, and receiving environments (estuaries and lakes) are upstream and/or downstream of the property. With either good or poor management practices influencing the water quality outcomes of these downstream receiving environments.
Paddock scale flow direction arrows, water flow pathways, and drainage areas surrounding an underpass. Overland flow or surficial runoff is then channelled through a network of culverts and open ditch drains and off the property.