Submission on the Draft Water Allocation Plan 2015-05-11
Here are some sections in the Draft WAP that I question.
(1) Draft WAP: page 13, 1.3.3 Aquifer Recharge and Discharge Processes.
“These declines are commonly observed in systems where no extraction from wells is occurring.”
I disagree with the inference that there is no connection between the lenses owing to the following statements:
“There is evidence through the chemistry that the southern and northern basins within the Southern Basins PWA are connected due to dolomite being present in the Uley Wanilla, below the Uley Wanilla formation. Magnesium traces have been picked up in town water supply bores which suggests that there is water coming through the tertiary sand aquifer from the northern basins: Uley Wanilla, and Uley East”.- Report to Natural Resources Committee 7th May 2013.
In the Technical Report: Science Support for the Musgrave and Southern Basins Prescribed Wells Areas Water Allocation Plan 2012/15 it states :
“ Significant discharge from Quaternary limestone aquifer occurs towards the southern boundaries of Uley East and Uley Wanilla lenses to the underlying Tertiary Sands (Evans et al 2009b)” and Page 25 this report : “Within the Uley South Basin, groundwater levels suggest there is potential for upward leakage from the underlying Tertiary Sands aquifer into the Quaternary Limestone aquifer” (Harrington et al. (2006).
In other words, water in Uley East is discharging down to the Tertiary Sands (where the clay aquatard is absent), and then upward leakage occurs, (water flows up,( again where the clay aquatard is absent) to the Quaternary Limestone of Uley South, so wouldn’t extractions from Uley South be contributing to the decline in water levels in Uley East?
(2) Draft WAP: Which of these statements is correct? Page 14 it states: “Historical rainfall data indicates above or below –average trends may persist for up to 25 years “ yet in the “Technical Report” it states: “Furthermore, Evans et al (2009b) indicates that above or below average rainfall trends have historically lasted up to 10 years”.
WAP: page 25: 126.96.36.199 Recharge Rate: The proposed level of extraction of around 5720 ML/yr, is 792 more than the metered usage for 2013/14, and higher than metered usages for 2012/13; 2011/12; and 2010/11.
Why is there an increase in level of extraction?
In this WAP the proposed 5720ML/yr level of extraction is achieved by taking 30% off of the recharge to go to the environment, (leaving it with just 30%) and giving it to consumption 70%. Refer to page 69 Table 14.
In DWLBC Report 2007/4 the recharge rate values were determined to be between 50-160 mm.
(3) Draft WAP: page 31: 2.3 Creation of Additional Consumptive Pools: Is this set up to accommodate Lincoln Minerals’ Water Access Entitlement ?
WAP: page 30: 188.8.131.52 Basement Management Areas
SKM Scoping Study Report states: “90% and 50% of recharge to the Tertiary and Basement aquifers is provided to maintain aquifer pressures and meet needs of GDE’s” There is a Water Access Entitlement for mining hanging over this aquifer, and the WAP states that there is a nominal amount available to meet future Ministers’ authorisations. Is this amount for future mining and how will this affect the aquifer pressures?
(4)Draft WAP: page 30: 2.2.3. Quaternary Lincoln North Management Area
“ licensees have had difficulties accessing the water resource due to water level declines. “ and “it is thought that these water level declines are driven by a significant period of below average rainfall and diminished recharge”
Could the diminished recharge also be the result of the dams put on the head waters of Greenpatch Creek in 1990? It has been observed that now, water does not flow down Greenpatch Creek until 275mm (11 inches) of rain has fallen.
Has 275mm/yr (11 inches of rainfall) been taken off the recharge calculation for the Lincoln Basin?
Wouldn’t expanding the boundaries of the PWA help solve this problem?
The Uley Basin receives recharge not only from rainfall directly over the Basin, but also from outside of the Prescribed Wells Area Boundary via runoff from uplands just to the north.
Shouldn’t the Prescribed Wells Area include this catchment?
(5) Draft WAP: page 35: 3.3.1 Wetlands: It states, “Those wetlands that depend on catchment water and are thought to be disconnected from the Quaternary aquifer, such as Big Swamp and Little Swamp (SKM 2009), were not considered to be GDE’s and thus are not considered to be current environmental values for the purpose of this Plan.”
I strongly disagree with not giving Big Swamp and Little Swamp environmental values in the current WAP. On the grounds that;
“There are several inland wetland areas on Eyre Peninsula that are listed in the Directory of Important Wetlands for South Australia. These include, Big Swamp, Little Swamp, Sleaford Mere, Lake Newland, and Lake Hamilton.”- Wetland Inventory Eyre Peninsula Seaman R.L.(2002)
In MERI Plan for the Southern Basins & Musgrave Prescribed Wells Area WAP (page 40). GDE Monitoring Site Selection it states:
Southern Basins: b. Big Swamp (high) :” was included in this analysis to demonstrate that it ranks highly (equal sixth) against the other sites for monitoring value, despite being equivocal in terms of groundwater dependence (and therefore at a disadvantage in this analysis). It is likely this would rank among the highest monitoring priorities if the groundwater reliance criteria were removed.” Yet it is recorded that: “Big Swamp is considered important in the overall water balance of the Uley Basin”(Harrington, Evans,& Zulfic 2006)
Also in SKM Scoping Study 2010 it states: “ In the Southern Basins area, mapped areas inferred to be obligate phreatophytes are present in small pockets in the north and east of the region, overlying the northern edges of Uley Wanilla and Uley East, surrounding Big Swamp as well as to the east near Lincoln-D and Tulka lenses.”
Little Swamp supports an annual coverage of Chara spp.- a significant resource for birds and other fauna, and should rate environmental protection too.
(6) Other GDEs that are over Uley South which have not been considered in the Draft WAP are,
1/ collapsed sinkholes.
SA Water has estimated from extensive mapping that there is roughly a sinkhole every seven hectares. There is about 75 millimetres per annum of recharge through the sinkholes out of a total of around 130/140millilitres per annum (just over half) –Natural Resources Report 7th May 2013
In SKM Eyre Peninsula Groundwater Ecosystem Scoping Study 2010 it states:
“Collapsed sinkholes provide shady and moist environments for plant forms, including Rock Fern (cheilanthes austrotenui folia). These areas are likely to provide habitat for unique flora and fauna species on the Eyre Peninsula. Some collapsed sinkholes may intersect the water table and act as drought refuge/ watering areas.
2/ Tussock Grassland and Facultative phreatophytes.
In SKM Eyre Peninsula Groundwater Dependent Ecosystems Scoping Study 18th March 2010 it states:
“In the Uley and Coffin Bay Basins, the areas of potential GDEs mostly comprise tussock grassland and facultative phreatophytes over shallow water tables or unknown depths to water. In the Uley Basin the greatest expanse occurs to the east of Uley South, near to associated extraction wells, and in the south and to the East of Uley East. A seasonal/intermittent freshwater lake connected to the quaternary aquifer with adjacent obligate and facultative phreatophytes and sedgeland also overlies the centre of Uley South, near extraction wells”
Areas of Cutting Grass remain over Uley South near the Cooroona, Paradise and Charlotte’s Water Holes. Cutting Grass, considered an endangered species, also representing an important food source for rare butterfly species (Grund 1997), is dependent on underground water (0~3m) for survival. The Cutting Grass Flats occur down-gradient of the Uley South public reticulated water supply borefield and therefore should have a high environmental risk value.
Where are the Environmental Protection Zones for these phreatophytes, sedgelands, seasonal swamps and sinkholes (important to recharge) ?
SKM Scoping Study also states: “the majority of the information available regarding water resources on Eyre Peninsula is focused on water supplies for human consumption and use by stock; there is a need for investigations regarding water requirements for biodiversity.”
More Phreatophyte sites were identified and marked on maps by participants at the consultative meeting on 24th April.
(7) Draft WAP: page 67. 5.1.13. The Risk Matrix.
“ Management with high accessibility risk and low environmental risk requires a high proportion allocated to users (Consumptive demand) to mitigate risk.”
I understand this to mean that the social and economic risk of not providing enough water over rides the risk to the basins of over extraction.
I do not agree with the allocation of Uley South recharge as 30% for the environment and 70% for consumptive demand.
Since 2004 Uley South lens alone is being required to supply a bigger and bigger volume of the allocated water. In this Draft WAP it has reached around 95%.
In 2007 Uley South provided around 70%. of the reticulated water – Technical Report DFW 2012/15. Page 3. 2.1 Background : “ The Uley South Lens in the Southern Basins PWA (fig. 1a) contributes around 70% to Eyre Peninsula’s total reticulated water demand (Zulfic, Harrington& Evans 2007)”
2010/11 Uley South provided on average 85% of reticulated water – SKM. A Risked-Based Approach March 2014 Report: “Between 2004/5 and 2010/11 extraction from Uley South provided on average more than 85% of the Southern Basins supply for SA Water. There is currently no alternate supply that could meet this volume.”
From2015 onwards Uley South will provide 95% of the reticulated water.
This DRAFT WAP: page 71 184.108.40.206 Licensed Demand: “ The majority of the extractions are from the Uley South Basin which accounts for around 95% of the total extractions from the Southern Basins”
This emphasises that the risk to Uley South environment ie. aquifer maintenance is as great as the risk of not meeting the consumptive demand.
The Risk Assessment Matrix should be at least 50% consumption and 50% environment. Otherwise the risk of not being able to provide water for critical human needs and or the risk to the resource- turning saline, is simply put off for another year until the annual review.
Technical Report DFW 2012/15. Seawater Intrusion
“Importantly, and counter-intuitively, “passive seawater intrusion” can occur when groundwater pumping results in landward ingress of freshwater-saltwater interface despite the hydraulic gradient of the freshwater aquifer still sloping towards the sea. Estimation of the rate at which seawater intrusion may occur is complex but it may occur abruptly.”
Why has the sustainable 60% environment and 40% consumption of the previous WAP been altered?
(8) Draft WAP:page 79. 5.4.4 Mining Industry
“Demand for water from the mining sector in Eyre Peninsula is expected to increase in the future, and mining operations can require significant volumes of water.”
5.4.1 Public Water Supply “ Mining operations may also source some of their water needs for production purposes from the Public Water Supply.”
“Lincoln Mineral Limited proposed to extract up to 2GL of water each year for dewatering.” “ there is considerable uncertainty about the impact of such extractions for dewatering on salinity and storage, although it was agreed that some impact was likely.” –SKM A Risk-based approach to Determining Consumptive and Aquifer Maintenance Pools March 2014 This should be rated as a high risk to the environment.
(9)Draft WAP: Page 17. 2 “Given the fragile nature of the Quaternary Limestone aquifer on the Eyre Peninsula, it is not possible to provide an assessment of the capacity of the resources in the same way as other groundwater resources in South Australia. In the Mallee and the South East for instance, the large and robust sedimentary aquifers enable a portion of the water stored to be considered as part of the resource capacity.”
Draft WAP Trigger Levels page 84: “Therefore the aquifer storage level of autumn 1993 has been chosen as the reference level.(at which storage is set to 100%) An important consideration for selection of the reference level is the availability of consistent monitoring locations that can be used for calculation of the storage level both historically and for the life of this plan”.
Yet in Natural Resources Report 7th May 2013it states: “ A number of long-term monitoring wells were established in Uley South in the 1960’s for water level monitoring. Some of them we (SA Water) have discounted because of their location and construction. SA Water has settled on three bores in the central basin downstream of its main production area as representative of what is happening with the basin water levels.”
Wouldn’t autumn 1975 be the optimum date to set as 100% full level ? It is the year before SA Water started pumping from Uley South. Quoting same report “ A second bore field was started in 1999. There was a significant drought through that period from about 1992 to 1999” ( except 1992 which had 766mm rainfall) “ and this corresponds to the lowest recorded water levels which were in 1999. Since that time pumping has increased with the extension of the bore field, but despite the rainfall remaining either average from 2009 to 2012 the basin has remained stable or slightly increasing.”
The drought broke in 2010 with a 608mm of recharge rainfall with follow up years of 575mm 2011; 421.5mm 2012; and 617.75mm 2013; so yes the basin would slightly increase, from the all time low of 1999.
The following statement from DWLBC 2007/4 Report may indicate that extractions had something to do with the all time low and not just climate. Ground Water Extractions Page 25 4.6 : “SA Water supplied extraction data for the 28 town water supply wells, 11 of which are located in Uley Wanilla and 17 are located within three bore fields in Uley South. The provided data for periods 1949-2005 for Uley Wanilla and 1976-2005 for Uley South were given as monthly totals for all wells in each lens. Total average yearly extraction from Uley Wanilla is ~1200ML. Total average yearly extraction from Uley South was 5000ML until 1999, when the well field was augmented to allow up to 8000ML average annual extraction. The maximum extractions from Uley Wanilla were 2800ML in 1961 and 7900ML from Uley South in 2000.”
In 2015, 95% of total extractions are from Uley South and that basin can now only provide 5720ML/yr providing it gets the bigger share of the annual recharge ie. 70% consumption and 30% environment.
Given the fragile nature of the Quaternary Limestone aquifer,
and that Uley South will provide 95% of the allocated water,
and that seawater intrusion could occur abruptly,
and that the recharge allocation has been reversed from, 60% environment and 40% consumption in the last WAP, to 30% environment 70% consumption in this WAP,
Perhaps the Mid Storage Level Trigger should become the Low Storage Level Trigger already .
Perhaps the following statement should be triggered. “If demand and supply projections indicate a gap is likely to exist within five years or less, the Minister will establish an independent planning process to consider management or supply options.”
By Julie Bassham
By Julie Bassham