Physical-chemical state

Changes to the hydrology of a wetland can affect:

• seasonality of flow
• no inflow spells
• low/base or flood flow
• rate of rise and fall of water levels.

Changes to no flows, base flows or flood flows will alter the time that the wetland is in a wet/dry state impacting wetland extent. Changes to seasonality and rate of rise/fall will impact biota migration/recruitment cues impacting sensitive species.

Biological impact

Changes to the seasonality, no flows, low/base flows, flood flows or the rate of rise/fall of water levels of a wetland can result in a loss of sensitive species.

Hydrology is the most important factor in wetland functioning and processes. Alterations to hydrology impacts on several other pressures, such as sediments, nutrients, organic matter, pH, conductivity and connectivity by altering inflows, dilution and outflows. In general, a change to the hydrological regime will result in a loss of sensitive species and change the wetland’s species composition and biodiversity which can lead to changes in almost all aspects of wetland ecology.