1. To specify a regulated flow regime that will sustain and where possible improve the current environmental values, dependent on water flows in the Broken River Basin; and
2. Provide advice to the Project Group on the environmental benefits of a variety of management options and operational scenarios.

• An understanding of ecosystem health, including important river and floodplain ecosystem components (e.g. fish or vegetation biodiversity or community structure), that may be affected by management decisions;
• Principles for assessing river condition and making recommendations to improve river health within a water management context, focussing on:
• The diversity of natural habitats and biota within the river channel, riparian zone and floodplain should be maintained (and where possible enhanced);
• The natural linkages between the river and the floodplain should be maintained;
• Natural metabolic functioning of aquatic ecosystems, such as primary productivity and respiration, should be suported.
• Assessing the river as a whole and operation of the river at the largest possible scale.

• Integration of knowledge of the historical and current environmental condition of streams in the study area (including the considerable experience and knowledge of the Broken system held by Panel members);
• Consultation with Goulburn Murray Water to clarify the operation of the system and aspects of its current condition;
• An intensive field trip, used to assess environmental conditions at 20 sites across the study area;
• Limited consultation with local landholders to gain their perspective of the river system;
• Analysis of hydrological data to identify changes to stream hydrology that have occurred since the regulation and diversion of water for agriculture and urban supply;
• Hydraulic modelling of sites representative of each reach of the Broken River;
• A series of workshops so that Panel members could develop a common understanding of the river system, important environmental values to be protected and how these values may have been affected by regulation and other catchment activities;
• The development of recommendations for a flow regime that will protect or enhance the environmental values identified for the Broken River system.

• The presence and operation of Lake Nillahcootie;
• Diversion of water from the Broken River and Holland’s Creek to supply Lake Mokoan, and operation of Lake Mokoan;
• The construction of irrigation supply and drainage schemes;
• The presence and operation of numerous weirs, both on the Broken River and Broken Creek;
• Progressive extraction of water from the Broken River and Broken Creek for irrigation and stock and domestic water supply;
• Changes to the form of the channel due to channelisation and snag removal; and
• Changes to floodplain drainage through the construction of levees and drains.

• Lake Nillahcootie releases;
• Lake Mokoan diversions;
• Lake Mokoan releases; and
• Casey’s Weir diversions.

• The largely natural pattern of the flow regime in the lower reaches of the Broken River and lower Holland’s Creek (including both high and low flows) as it maintains geomorphological, biological and ecological processes;
• Habitat diversity in the lower reaches of the Broken River, including in-stream features such as large woody debris, riffles, pools, bars, anabranches, the littoral fringe, flood runners, and floodplain and wetland/billabong features in the nearby landscape;
• Threatened species (flora and fauna), including up to ten native fish species of State and national conservation significance and icon species such as Murray cod;
• Riparian vegetation, especially in the lower Broken River and along Broken Creek. The remnant riparian and floodplain vegetation also provides important habitat for threatened species (fish, birds, amphibians) whose natural habitat in the region has been greatly reduced since European settlement;
• Connectivity between the river channel and its floodplain that maintains floodplain function;
• Links with the Goulburn and Murray Rivers, with the Broken River and Broken Creek being important for water yield and fish migration.

• Altered flow regime;
• Altered floodplain drainage patterns;
• Potential cold water releases;
• Introduced fish species;
• Barriers to fish migration;
• Clearing of riparian vegetation;
• Weed invasion (terrestrial or aquatic);
• Bed and bank erosion;
• Channel realignment and excavation;
• Sediment inputs from tributaries and due to past river management works
• Livestock access;
• Stormwater pollution;
• Septic tank contamination;
• Poor water quality from Lake Mokoan;
• Impact of algal blooms;
• Contaminants carried in road runoff;
• Discharge of irrigation drainage.

• River hydrology has been altered, with a reduction in higher flows as a result of regulation at all three reaches of the Broken River. Low flows are now greater than natural in the upper two reaches but are reduced in Reach 3. The effect on flood frequencies is small at all three sites, with Reach 2 being most affected.
• River geomorphology remains largely unaffected by flow regulation;
• Water quality has been affected by inputs of nutrients, sediments and turbidity, including irrigation drainage, runoff from agricultural land and releases from Lake Mokoan.
• Riparian and aquatic vegetation has been affected by wetter conditions in upper reach of Broken River and by disturbances such as clearance and livestock access across the catchments. Floodplain wetlands are likely to have been affected by isolation form the river channels (due to levees) and land management practices (e.g. livestock access);
• Macroinvertebrates are unaffected by river regulation in upstream areas. The decline in macroinvertebrate communities in downstream areas is probably due to multiple catchment impacts;
• Dams and weirs that act as barriers to migration have affected native fish populations, including threatened species. The extent of reduced habitat availability due to lower than natural flows in the lower Broken River reach needs to be confirmed. The potential effect of cold water releases from Lake Nillahcootie also requires confirmation, although flows from Back Creek are likely to dampen the extent of temperature depression when cold water releases occur.
• The connection between the river channel and its floodplain has been largely unaffected by flow regulation from the dams. However, river-floodplain connections have been altered by the presence of levees in the vicinity of Benalla and along the lower Broken Creek.

• Maintain minimum winter flow of 30 ML/d or natural at Moorngag while Lake Nillahcootie fills or when water is being transferred to Lake Mokoan. This flow is to pass along the rest of the reach and over Broken Weir;
• Apply a flow reduction target of Q2 > 0.65Q1 (Q2 = flow on day 2, Q1 = flow on day 1) when reducing regulated releases (e.g. when reducing flows from Lake Nillahcootie when filling the dam);
• Apply a rule of Q2 < 2.1Q1 when increasing regulated releases from Lake Nillahcootie.

Broken River from Broken Weir to Casey’s Weir:

• Maintain summer flow above a minimum of 22 ML/d or natural. This will be sufficient to maintain slow water habitat for juvenile fish also (20 ML/d). Compliance should be measured at Broken Weir and include the 22 ML/d (or natural) and additional flow to meet diversion needs along the reach;
• Apply flow reduction target of Q2 > 0.7Q1 when adjusting flows (e.g. when diverting to Lake Mokoan; when reducing flows during the irrigation season).
• Apply a rule of Q2 < 1.5Q1 when increasing regulated releases.

Broken River from Casey’s Weir to the Goulburn River:

• Maintain flow above a minimum of 25 ML/d or natural downstream of Casey’s Weir. This will be sufficient to maintain slow water habitat for juvenile fish also (20 ML/d). Compliance should be measured at Gowangardie Weir and include the 25 ML/d (or natural) plus flows to meet diversion demands downstream of Gowangardie Weir;
• Apply flow reduction target of Q2 > 0.55Q1 when adjusting flows (e.g. when diverting to Lake Mokoan; when reducing flows at the end of the irrigation season).
• Apply a rule of Q2 < 1.8Q1 when increasing regulated releases.

• Maintain flow above a minimum of 12 ML/d or natural downstream of Holland’s Weir when Lake Mokoan is being filled.

• Existing management of Lake Mokoan continues according to current levels of demand, current diversion and release patterns, and the reservoir being closed in summer-autumn months for 9 years in 10 (the basis of previous discussion on environmental values and environmental flows);
• Decommissioning the reservoir, where Lake Mokoan is no longer used as a supply of irrigation water and there are no diversions to, or releases from the reservoir to meet downstream demand;
• Unconstrained operation of the reservoir, where diversions to, and releases from the reservoir are unconstrained by water quality and algal bloom problems, the reservoir remains open all year round and there is a full uptake of existing licenses.

• The lower Broken River is an example of a lowland river that generally is in good health. This is a relatively rare thing and considered to be of greater ecological value than the upper reach of the Broken River, which is a foothill stream of moderate to good condition.
• Reach 3 is more likely to support an abundant and a diverse range of native fish species than is Reach 1, including Murray cod, trout cod, golden perch and blackfish. Any move to enhance native fish populations in this reach would be valuable. Reach 3 is also much longer than Reach 2 and is closest to the Goulburn and Murray Rivers. Most fish migrations from these rivers will occur along Reach 3.
• Relatively little is known about the ecology of the river upstream of Benalla. At this stage, priority should go to those reaches known to have a high conservation value.
• The decommissioning scenario poses fewer risks to the health of the Goulburn and Murray Rivers, as the largely natural winter/spring flows resulting from this scenario are complementary to the natural flow regime of these rivers.

• Reduction in unnatural overflows to wetlands such as Moodies Swamp and Lake Rowan;
• Changes to geomorphic processes and increased habitat diversity in the long term;
• Increased native vegetation both in the creek channel and in the riparian zone;
• Conditions less favourable to weeds species such as willows;

• Develop clear rehabilitation objectives for Broken Creek. Given that the current condition of instream values in Broken Creek is poor, rehabilitation should be directed towards maximising/improving landscape values.
• Return the Broken Creek to an ephemeral stream between Waggarandall Weir and Katamatite. Potential benefits include extending the range of native fish, control of carp and the management of willows.
• Control livestock access to Broken Creek.
• Revegetate stream with native (indigenous) species.
• Support the move to include high value riparian areas in a proposed State park.
• Develop carp control strategy to complement the carp control plan for Barmah.
• Continue willow removal program.
• Continue the fish passage/weir removal program after reviewing weir pools with apparent good environmental values.
• Continue and possibly increase the rate of investment in water quality and river health initiatives in line with the Goulburn Broken CMA’s waterway health program and water quality strategy.
• Review the benefits of weir draw down trials being conducted elsewhere in the Murray Darling Bin.
• Support the call for monitoring the effects of management actions (ISC, WQ, length of stream fenced of and revegetated, increased native fish populations etc.). If moves to return intermittency of flow to the stream are acted upon, then monitoring ecological responses will be critical.
• Develop and implement a pest and fire management plans to complement rehabilitation plans.
• Cessation of any further channelisation works. If in-stream works such as sediment removal are carried out (e.g. from weir pools), care must be taken to minimise sediment input and transport in the stream as current levels of suspended particulate matter are unacceptably high.
• Ban of removal of wood from the riparian zone.
• Closely monitor ecological responses to the changed flow regime that accompanies installation of the Tungemah pipeline.

• Continued efforts to reduce nutrients, sediment and turbidity in releases from Lake Nillahcootie and Lake Mokoan;
• Rehabilitation of native vegetation in the riparian zone of Reach 1 and Reach 2;
• Prevent further small weir building within the main channel of the Broken River;
• Evaluation of the potential to reinstate in-stream habitat such as snags in areas previously cleared by ‘river improvement’ works;
• Investigating the significance of slugs of sand to altered habitat diversity (Reaches 2 and 3);
• Limiting livestock access to waterways;
• Implementing pest control strategies, for example for carp;
• Continue the program of providing fish passage past barriers such as weirs. Priority should go to Gowangardie Weir, Casey’s Weir and Broken Weir on the Broken River, Holland’s Weir on Holland’s Creek, and continuation of the fish passage program on Broken Creek;
• Ensure proper maintenance of existing fishways;
• Encouraging responsible recreational fishing for native species.

• More constant water levels that favour invasive species such as willows and carp;
• Potential cold water releases that affect the biology of riverine biota;
• Change in macroinvertebrate abundance and species composition;
• Increased potential for washout of larval and juvenile fish;
• Less habitat for submerged aquatic macrophytes and, as a consequence, less habitat for macroinvertebrates and small fish;
• Increased sediment movement that disrupts biofilms and microphytobenthos that are a potential source of food for other biota;
• Increased bank erosion due to increased saturation of the bed and banks.