Vegetation Monitoring in the ColligenCreek System (2015-2018)

ILWS Strategic Research Area

Sustainable Water

Funding

Murray Local Land Services, $70,000

Investigators/researchers

Professor Robyn Watts, Sascha Healy from NSW OEH

Description

Riverbank and aquatic vegetation support riverine food webs and provide habitat for fish, invertebrates, frogs and birds. The water regime in a river system can affect the growth and maintenance of adult plants and can strongly influence the reproductive cycle, including flowering, dispersal, germination and recruitment. Riverbank plant survival and growth is particularly affected by the frequency and duration of inundation. Frequent inundation can delay reproduction, whilst long duration of inundation can reduce growth or survival.

The Edward-Wakool River System is a large anabranch system of the River Murray and is considered to be important for its high native species richness and diversity including threatened and endangered fish, frogs, mammals, and riparian plants. The Commonwealth Environmental Water Office, as part of their water planning in collaboration with stakeholders, intends to deliver Commonwealth environmental water to Colligen Creek to trial a new operational arrangement with WaterNSW to maintain a slightly higher base flow and manage the recession of rain rejection events . Inundation of riverbanks can create low flow zones (slackwaters) having low velocities and shallow depths. It is predicted that the environmental watering actions will improve vegetation cover and diversity in Colligen Creek, and in turn may assist the recovery of native fish in the system.

For this project researchers will undertake:

• A three year monitoring program to evaluate the response of aquatic and riverbank vegetation to environmental watering in Colligen Creek, and
• Inundation modelling of river reaches in Colligen Creek to estimate the extent of wetted benthic surface area and the area of velocity zones under different flow scenarios and determine the relationships between discharge, flow heights and area of inundation to inform future water delivery decision making.

Outcomes

This information will improve our knowledge of aquatic and riverbank vegetation responses to in-channel flows and contribute to more efficient and better targeted used of environmental water. The project will complement the current Edward-Wakool Long-Term Intervention Monitoring project funded by the Commonwealth Department of the Environment.

Contact:
Prof Robyn Watts
Charles Sturt University Albury-Wodonga
email

November 2015