Farm runoff Managing nutrient pollution

For more information, contact Scientific Services Water and Coastal Science Office of Environment and Heritage Ph. 9995 5000

Nutrient export monitoring The Hawkesbury-Nepean River Recovery Program aims to improve river health below the major water supply dams by increasing the water available for environmental flows and reducing nutrient loads in the river. As part of this project, a range of measures have been implemented do reduce the amount of nutrients entering the river from farms.

Farm runoff in the Hawkesbury-Nepean catchment has been monitored to help determine:

• the amount of nutrients in the runoff • the effectiveness of different nutrient management measures • the level of nutrient export reductions achieved by the Hawkesbury-Nepean River Recovery Program initiatives.

The Hawkesbury-Nepean River Recovery Program is funded by the Australian Government through the Water for the Future Program and is managed by the NSW Office of the Hawkesbury-Nepean.

Photograph taken by Adam McSorley

© State of New South Wales through the Office of the Hawkesbury-Nepean, 2011. This material may be reproduced in whole or in part for educational and non-commercial use, providing the meaning is unchanged and its source, publisher and authorship are clearly and correctly acknowledged. Disclaimer: While every reasonable effort has been made to ensure that this document is correct at the time of publication, the State of New South Wales, its agents and employees, disclaim any and all liability to any person in respect of anything or the consequences of anything done or omitted to be done in reliance upon the whole or any part of this document.

Photograph taken by Adam McSorley

Photograph taken by Adam McSorley

Agricultural runoff Why manage runoff from agriculture?

Runoff from agricultural land can carry large amounts of nitrogen, phosphorus, and sediment. Excess nitrogen and phosphorus can cause algal blooms in waterways that can be toxic to humans, livestock, and fish. Sediment can clog fish gills, smother plants and can reduce light penetra-tion in the water. Without light, aquatic plants on the river bed cannot survive. Aquatic plants are important for commercial and recreational fishing as they provide a habitat and food source for fish.

Managing agricultural runoff

Reducing agricultural runoff has a positive effect on river health, increas-ing water clarity and the abundance of fish and aquatic plants. Agricultural runoff can be managed by: • fencing cattle away from streams • maintaining healthy vegetation around streams • capturing and re-using runoff in retention ponds • recycling greenhouse wastewater • covering or enclosing fertiliser and manure storages • reducing fertiliser use through better targeting • upgrading to more efficient irrigation systems • mechanically aerating compacted soils to increase infiltration.

Nitrogen and phosphorus from agriculture fuel the growth of algae.

Algae and sediment reduce light penetration, turning the water brown/green.

Savings from runoff management

If farm runoff is captured in a retention pond or dam it can be reused to irrigate crops or pasture. This will not only reduce the cost of water but, because of the high level of nutrients in the runoff, it will also reduce fertiliser costs.

Without fencing, livestock can Recycling greenhouse wastewater enter streams, trample vegeta- reduces fertiliser and water requirements tion and pollute the water with and decreases the amount of pollutants urine, faeces, and bacteria. discharged to the environment.

Without proper manage-ment, runoff from agriculture pollutes waterways, causing environmental degradation and potential human health risks.

Degraded river Healthy river

Reduced light limits or prevents aquatic plant growth.

Without aquatic plants, river bed sediments can be stirred up by water movement, further reducing light penetration.

Vegetation acts as a buffer by slowing the flow of water, trapping sediment and absorbing nutrients.

Waste from livestock can be re-used to fertilise pasture, improving pasture growth and reducing effluent pollution.

Retention ponds capture nutrients and sediment in runoff. Water from ponds can be reused to irrigate fields.

With less agricultural runoff, the river water is clearer and there is a greater abundance of native fish and aquatic plants.