sediment mobilisation and deposition. Supplementing (piggy-backing) catchment inflows to ensure bankfull and overbank events to inundate riparian and floodplain assets (25,000 – 40,000 ML/d, minimum 4-5 days duration, 7-10 years out of 10***). Bank any excess water for subsequent years. macroinvertebrates. Planktonic algae production rates, biomass levels and community composition more resembling un-impacted sites, promoting dynamic and diverse food webs. Pre-spawning and movement cues for some native fish species (e.g. golden perch). Maintain natural rates of sediment mobilisation and deposition. Supplementing (piggy-backing) catchment inflows to ensure bankfull and overbank events to inundate riparian and floodplain assets (25,000 – 40,000 ML/d, minimum 4-5 days duration, 7-10 years out of 10***). Banking of water to supplement catchment inflows for bankfull and overbank events in subsequent years. diverse food webs. Pre-spawning and movement cues for some native fish species (e.g. golden perch). Maintain natural rates of sediment mobilisation and deposition. Supplementing (piggy-backing) catchment inflows to ensure bankfull and overbank events to inundate riparian and floodplain assets (25,000 – 40,000 ML/d, minimum 4-5 days duration, 7-10 years out of 10***). Bank any excess water for subsequent years. *An upper limit is applied to summer freshes to avoid increased rates of sediment deposition in pools. See Cottingham et al. (2007) for further explanation. **Information on the frequency, magnitude and duration of freshes is contained in Cottingham et al. (2003). ***For further details, see DSE (2011).
Table : Flow monitoring along the Goulburn River. Reach Number Reach Description Relevant Hydrographic Stations Site ID Site Name Adequacy of Gauge (pers comm. Leon Tepper – Thiess Tatura) 1 Lake Eildon to Molesworth 405203C Goulburn River @ Eildon There is an unstable stage/discharge relationship at this site due to seasonal weed growth along the gauging station reach. This has most impact on flows of <1,000 ML/d. For flows between 1,000 and 4,000 ML/d the uncertainty is better than 8% at 95% confidence limit. 2 Molesworth to Seymour 405201B Goulburn River @ Trawool Likely issues with lower flows (<1,000 ML/d). The site relies on a natural channel control giving poor low flow sensitivity and a mildly unstable stage discharge relationship. Low flow gaugings are undertaken 2 km upstream of the site. 3 Seymour to Nagambie 405202B Goulburn River @ Seymour The stage/discharge relationship is stable. Flow data uncertainty is better than 4% at 95% confidence level. 4 Goulburn Weir to Shepparton 405259A Goulburn River @ Goulburn Weir Flood measurement only >3.5 m. Upon request only. 405200A Goulburn River @ Murchison The conventional method of monitoring flow using a stage discharge relationship is not adequate for this site. The site is subject to hysteresis, different types of loop rating curves occur
Maintain diversity of riverbank vegetation. Reduce extent and impact of weeds. Maintain continuity and cover of riverbank vegetation. Enhance the extent and diversity of aquatic vegetation. isolation from the wider water regime. Macroinvertebrates Trophic structure and diversity with a more balanced representation of all functional groups. Ausrivas O/E scores = Band A. Biomass equivalent to rivers elsewhere (e.g. Ovens). Maintain dynamic, diverse food webs that support higher organisms and contribute to river health. As above. As above. Native fish Suitable in-channel habitat for all life stages. Suitable off-channel habitat for all life stages. Passage for all life stages. Cues for adult migration during spawning season. Access to floodplain and habitats for spawning and/or larval rearing. Low flows recruitment and survival. Floodplain and bench inundation for exchange of food and organic material between floodplain and channel. As above. As above. Geomorphology Maintain natural rates of sediment dynamics (erosion and deposition) and natural patterns of geomorphic diversity. Existing monitoring is appropriate for larger channel-forming events (i.e. approaching bankfull discharge). Additional monitoring can be considered to evaluate sediment movement and pool depth for smaller flow freshes. Phytoplankton, periphyton and macrophyte production Phytoplankton, periphyton and macrophyte production rates, biomass levels and community composition more resembling sites to support dynamic, diverse food webs. None. Additional monitoring is required. The GB CMA is investigating options to use the volume stored in Goulburn Weir to release flows to coincide with natural flow peaks along the Broken River, thereby providing enhanced flows in the Lower Goulburn River downstream of Shepparton. The volume released from Goulburn Weir would then require some supplementing from Lake Eildon releases. This would involve some operational adjustments, such as managing deliveries along the irrigation channels supplied from Goulburn Weir. This is currently being considered by the GB CMA, but may only be feasible during winter. If the use of Goulburn Weir is not possible, opportunities to deliver the desired
flows (in the pre-regulation regime) F026 Proportion of time water level is above a specified depth above bed corresponding to the m% exceedence flows (in the pre-regulation regime) m = 10, 20, 30, …, 90 F027 Proportion of time flow exceeds 24,000 Ml/d
Geo2 Avoid slumping. F023 Su Excessive rates of fall in river level. Geo3 Maintain pool depth. F026 Su Unseasonal events that fill pools with sediment but do not flush them. Geo6 Maintain natural rates of geomorphic disturbance. F006 Dec-Apr High velocity discharge increases disturbance of sand substrates and aquatic macrophytes.
5: VEFMAP 4 5 Summary of VEFMAP monitoring arrangements for environmental water use in the Goulburn River (from SKM 2007, Chee et al. 2006). Flow component Hypotheses Indicator(s) Monitoring sites Frequency Considerations for this watering options project Geomorphology Winter/spring freshes Does increased frequency of winter-spring fresh events: a) Increase the frequency of geomorphologically significant events (e.g. redistribution of bed and bank sediments)? b) Increase channel complexity (e.g. areas of the stream bed which are flushed free of fine deposits, deeper pools and variability in bench elevations)? c) Increase channel width and depth? d) Increase rates of meander development (i.e. bank erosion on the outside bank, point bar development, increased sinuosity and eventually bend cut-off and billabong formation)? Flow and physical habitat (channel dimensions) to assess: Frequency of channel disturbances Frequency of bed disturbances Rate of bench deposition Bed complexity Bench development and variability Mean channel top width, cross-section area and thalweg depth Bank erosion on outside of meander bends Point bar development. Two physical habitat sites in each of Reach 4 and Reach 5. Three flow sites in Reach 4 and two flow sites in Reach 5. Physical habitat - first year (2008) and after channel forming events thereafter. Flow – continuous at all sites. VEFMAP provides baseline information for assessing effects of environmental water. May require repeat measurements to provide ‘before’ data if channel dimensions have not been surveyed after recent (2010) flood events. Bankfull and overbank flows As above As above As above As above As above Habitat & macroinvertebrates Summer/autumn low flows and freshes Do implemented environmental flows maintain in-channel shallow and slow water areas? Do implemented environmental flows maintain adequate area Shallow and slow water areas Riffle/run depth and area Two physical habitat sites in each of Reach 4 and Reach 5. Physical habitat - first year (2008) and after channel forming events thereafter. As above VEFMAP sampling was not designed to assess short-term changes. Will require more
and depth of at least 0.1 metres in shallow, slow water and riffle/run habitats? Do implemented environmental flows maintain adequate volume and depth in permanent pools? Do implemented environmental flows maintain connectivity? Do implemented environmental flows maintain macroinvertebrate community structure? Do implemented environmental flows increase fish recruitment? Do implemented environmental flows maintain fish assemblages and/or population structure? Permanent pool depth and volume Connectivity Number of invertebrate families index AUSRIVAS score SIGNAL biotic index EPT biotic index Presence/absence and number of taxa See conceptual model for Fish Spawning & Recruitment Fish species composition Relative abundance of adult/sub-adult native and exotic fish species Population structure and size class distribution of native and exotic fish species. Four macroinvertebrate sites in Reach 4. No sites in Reach 5. See also native fish monitoring (below). Annually frequent ‘before’ and ‘after’ sampling if the effects of environmental water are to be assessed in isolation. Winter/spring baseflows Do implemented environmental flows increase in-channel shallow and slow water areas? Do implemented environmental flows increase area of riffle and/or run habitat? Shallow and slow water areas Riffle and/or run area Two physical habitat sites in each of Reach 4 and Reach 5. Four macroinvertebrate Annually As above VEFMAP sampling was not designed to assess short-term changes. Will require more frequent ‘before’ and ‘after’ sampling if the effects of
Do implemented environmental flows increase volume of permanent pool habitats? Do implemented environmental flows result in sustained inundation of in-channel macrophytes, channel edge macrophytes, tree roots, woody debris, branch piles, in channel bars, overhanging or undercut banks? Do implemented environmental flows increase abundance of macrophytes? Do implemented environmental flows improve macroinvertebrate community structure? Do implemented environmental flows improve fish assemblages and/or population structure? Permanent pool depth and volume Inundation of representative physical habitat features See conceptual model for Aquatic and Riparian Vegetation Cover of submerged and amphibious species Cover of submerged and amphibious species Number of invertebrate families index AUSRIVAS score SIGNAL biotic index EPT biotic index Presence/absence and number of taxa Fish species composition Relative abundance of adult/sub-adult native and exotic fish species Population structure and size class distribution of native and exotic fish species. sites in Reach 4. No sites in Reach 5. See also native fish monitoring (below). environmental water are to be assessed in isolation.
Winter/spring freshes Do implemented environmental flows increase area of riffle and/or run habitat? Do implemented environmental flows increase volume of pool habitats? Do implemented environmental flows result in temporary inundation of higher-level channel edge macrophytes, tree roots, woody debris, bars, benches, overhanging/undercut banks? Do implemented environmental flows improve macroinvertebrate community structure? Do implemented environmental flows improve fish assemblages and/or population structure? Riffle and/or run area Permanent pool depth and volume Inundation of higher elevation representative physical habitat features Number of invertebrate families index AUSRIVAS score SIGNAL biotic index EPT biotic index Presence/absence and number of taxa Fish species composition Relative abundance of adult/sub-adult native and exotic fish species Population structure and size class distribution of native and exotic fish species. Two physical habitat sites in each of Reach 4 and Reach 5. Four macroinvertebrate sites in Reach 4. No sites in Reach 5. See also native fish monitoring (below). Annually As above Aquatic & riparian vegetation
Spring freshes & bankfull flows Do implemented environmental flows wet high-level benches, upper banks, runners and anabranches in Zones B* & C*? Do implemented environmental flows increase germination and establishment of terrestrial ‘damp’, terrestrial ‘dry’ and amphibious fluctuation-tolerator species? Do implemented environmental flows improve canopy condition of in situ riparian trees and shrubs? Wetting of geomorphic features in Zones B* & C* Species composition, number of amphibious and terrestrial species in Zones B* & C* Proportion of exotic plant species Germination of seedlings of over storey and mid-storey species Canopy condition. As above As above As above Summer baseflow Do implemented environmental flows maintain area of in-channel shallow and slow water and run habitats? Do implemented environmental flows wet in-channel bars, benches, channel edges, runners and anabranches in Zone A*? Do implemented environmental flows improve canopy condition of adjacent riparian trees and shrubs? See conceptual model for Habitat Processes Shallow and slow water areas Run depth and area. Wetting of geomorphic features in Zone A* Canopy condition. As above As above As above Native fish
Autumn-early winter freshes/bankfull flows Do implemented environmental flows trigger spawning of diadromous fish? (Only relevant in river reaches inhabited by diadromous fish species such as galaxiids, eels and Australian grayling) Presence/absence of diadromous fish larvae Six sites in each of Reach 4 and 5 Annually VEFMAP may be appropriate for considering effects of environmental water, but it may also be difficult to separate from other influences, including recent flow history (i.e. antecedent conditions). Winter-spring baseflows freshes Do implemented environmental flows increase overall quantity and diversity of in stream habitat? See conceptual model for Habitat Processes • Shallow and slow water areas • Run area • Permanent pool depth and volume • Inundation of physical habitat features • Inundation of higher elevation physical habitat features • In-channel and littoral cover of macrophytes. As above As above As above Spring-early summer bankfull flows Do implemented environmental flows inundate low-lying runners and anabranches to create increased slackwater habitat? Do implemented environmental flows increase the number of fish completing larval stages? Area of slackwater habitat in runners and anabranches Density of post-larval fish. As above As above As above Spring-early summer base flows Do implemented environmental flows provide appropriate conditions for spawning and larval production of ‘low flow specialist’ and generalist fish Presence/absence of ‘low flow specialist’ and generalist fish larvae As above As above As above
species? Do implemented environmental flows maintain adequate in stream habitat for adult and larval fish? Do implemented environmental flows increase the number of fish completing larval stages? See conceptual model for Habitat Processes • Shallow and slow water area • Run area • Permanent pool depth and volume • Connectivity Density of post-larval fish. Spring-early summer overbank flows Do implemented environmental flows inundate low-lying runners and anabranches to create increased slackwater habitat? Do implemented environmental flows inundate floodplain areas to create increased slackwater habitat? Do implemented environmental flows provide appropriate conditions for spawning and larval production of ‘flood specialist’ non-diadromous fish species? Do implemented environmental flows increase the number of fish completing larval stages? Area of slackwater habitat in runners and anabranches Area of slackwater habitat in floodplain Presence/absence of ‘flood specialist’ fish larvae Density of post-larval fish. As above As above As above Summer-autumn low flows Do implemented environmental flows maintain adequate in stream habitat for adult and larval fish? See conceptual model for Habitat Processes • Shallow and slow water area • Run area • Permanent pool depth and volume As above As above As above