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1910
13 April 1910
1950
14 September 1950
Water Supply Schemes For Mudgee & Gulgong
At the request of Mudgee Municipal Council and Gulgong Shire Council, the Minister for Public Works and Local Government (Mr. J. J. Cahill, M.L.A.) recently arranged for a Departmental engineer to make a detailed investigation into all possible water supply sources in the Gulgong - Mudgee districts.
In an advice to Gulgong Shire Council, the Minister pointed that since the water supply requirements of Mudgee and Gulgong might be provided from a single storage, they had been considered as a joint problem.
Details of six systems were forwarded, three covering both Mudgee and Gulgong, the first mentioned being estimated to cost £382,100, the second £368 600 and the other £282,100. Schemes for Mudgee only are estimated to cost £186,000 and £34,000 respectively, and one for Gulgong alone (from underground sources) at £17,000.
Both Councils have the schemes under consideration.
The Minister furnished the following report: -
EXISTING SYSTEMS. Mudgee is supplied by a series of four wells on the flats just north of the town between the Cudgegong River and Lawson's Creek. None of these wells give continuous supply and in dry seasons any one of them can only be operated for a short period after which it has to be shut off for the water level to recover. In times of drought the total available supply from these wells may be no more than 250,000 gallons per day. This supply was recently augmented by the installation of a bore and pump with 8" rising main on the Burrundulla flats south east of Mudgee. This is equipped with a 7,500 g.p.h. pump which has so far been able to operate 24 hours per day without overdrawing the bore supply. All the waters are fairly hard, but the quality is otherwise satisfactory.
Another source of supply to Mudgee is the old storage on Red bank Creek. This is not a reliable supply in dry seasons, but it makes a useful contribution in normal or wet seasons and it has been calculated that in recent years the gravitation supply from the Redbank storage has been as much as 70 million gallons per annum.
Gulgong is supplied from the Wait-a-while well, which gives an intermittent supply. Here again the pumps must be shut off after a short period of operation in order to enable supply to recover. A supplementary bore was recently put down a little to the north of this well and should be in operation shortly. This bore is equipped with a 5,000 G.P.H. pump, but it is not yet known whether it will give continuous service in dry seasons. Gulgong is looking to the future installation of a sewerage system and improvement of its present inadequate supply is very desirable.
POPULATION AND CONSUMPTION. The 1947 census shows the population of Mudgee at 4,178 in 984 occupied premises. The 1949 Mudgee half-yearly reports show a population of 5,200 with 1,250 connections. The ratios of occupants per premises are comparable and the Council's estimate of population is considered reasonable. The present demand at Mudgee is about 120 m.g.p.a. and an augmentation could be designed to supply a future demand of 150 m.g.p.a. at a maximum rate daily of 850,000 g.p.d.
Gulgong has a population estimated by the Council at 1,570 and a present demand of about 25 m.g.p.a. An augmentation could be designed to supply 40 m.g.p.a. at a maximum daily rate of 220,000 g.p.d.
In considering a joint supply the design could therefore provide for a demand of 190 m.g.p.a. at a maximum rate of supply of 1,070,000 g.p.a.
The following brief comments are offered on a number of possible sources for a surface supply which were investigated and found to be useless for the reasons indicated:
Meroo Creek at Windeyer. - There is a good storage site a mile or so below Windeyer but the site is suited to a large project rather than to the small one required to serve Mudgee and Gulgong and the cost of power for pumping over Grattai Hills would be excessive.
Lawson's Creek. - A storage on the lower reaches of this creek is not practicable because an expensive railway relocation would be required.
Bara, Eurundury and Stoney Creeks and the upper reaches of Cooyal Creek offer no storage possibilities. Surface supplies from Wyaldra, Slap Dash, McDonald's and Burrundulla Creeks were eliminated for the same reason.
The headwaters of the Goulburn river were not considered because it is understood that this source is to be developed by the Ulan County Council for its proposed power station at Ulan.
In the search for supply from a surface storage investigation was thus narrowed down to the following:-
(a) Storage on the Cudgegong River near Cudgegong.
(b) Storage on the Cudgegong River at Apple Tree Plat.
(c) Storage on the Cudgegong River near Cullenbone.
(d) Green Gully Creek.
Consideration has also been given to a possible augmentation to Mudgee from underground sources (System 'E') and to an augmentation to the Gulgong supply (system 'F') from underground sources.
Each of these will be considered in sufficient detail to set out its salient engineering and economic features. The several estimates for dams are based on the known costs of comparable structures in other parts of the State but the figures set down should only be regarded as provisional and are liable to substantial increase, if foundations conditions are not as satisfactory as have been assumed.
Storage from Cudgegong River
System "a" Supply to Mudgee and Gulgong from a storage on the Cudgegong River near the village of Cudgegong.
This site is about 3 miles upstream of the village of Cudgegong and has many good features. The site is a fairly narrow gorge with steep rock slopes and with a good storage basin upstream. The site would probably be suitable for a concrete arched dam below which a pumping station could be equipped with duplicate 50,000 g.p.h. pumps. These would deliver to a balance tank on the slopes near the dam from which the water would gravitate to Mudgee through 137,000 feet of 12" pipe. At Mudgee a new 500,000 gallon service reservoir would be constructed in Mud gee Park and supply to Gulgong would be arranged through 4,600 feet of 10" pipe and 90,000 feet of 6" pipe. Duplicate 10,000 g.p.h boosters would be located at a convenient point along the 6" pipeline for delivery to the existing Gulgong service reservoir. The Mudgee distribution system would be improved by the 10" pipe referred to above, extending from the new reservoir along Court Street to Church Street, and an 8" pipe along Market from Court to Church Street. With the 12" gravitation main coming down Church Street to and along Nicholson Street to Mudgee Park this would provide a ring main around the greater part of Mudgee.
A tentative estimate of the capital cost is £382,100. Annual charges (for bulk supply only) are £18,828. It is realised that the present cost of power in this district is around 2d. per kwh, but the lower rate is adopted as a basis for selection of a major augmentation in view of the expected reduction of rates in a few years time when the proposed Ulan power station comes into operation. In calculating the cost of power it is assumed that an average of 50 m.g.p.a. is supplied by gravity from the Redbank storage.
Storage Dam At Apple Tree Flat
System “B”. Supply to Mudgee and Gulgong from storage dam at Apple Tree Flat.
This Apple Tree Flat Dam site has been investigated by the Water Conservation and Irrigation Commission in connection with a proposal to supply irrigation water to the Mudgee Flats. This proposal contemplated an earth dam about 150 ft. high with a spillway over a spur on the right bank and thence discharging into another valley which enters the Cudgegong River some way downstream of the dam site. Since there is no present intention of proceeding with this major work, this investigation deals with a smaller structure suitable for water supply purposes only. This would require a gravity type concrete structure about 40ft. high from which a booster station would deliver through a 12" rising main to Mudgee. The improvements at Mudgee and the connection to Gulgong would be identical with that considered in system 'A'.
Capital Cost is £368,600 and annual charges (for bulk supply only) £17,829.
Cudgegong River Near Cullenbone
System "C". Supply to Mudgee and Gulgong from a storage dam on the Cudgegong river near Cullen bone.
Since it is obviously desirable to eliminate the long pipeline from a storage dam to Mudgee involved in both Systems 'A' and 'B', a careful investigation was made of the storage possibilities on the Cudgegong River between Mudgee and Beryl. Perhaps the best of these is immediately downstream of the Cullenbone School but a storage here would involve submergence of a new reinforced concrete bridge over McDonald's Creek and considerable road relocations. An alternative possibility is a fairly open gorge about two miles downstream of Cullenbone in the north west corner of portion 5, Parish of Piambong. A fairly low earth filled dam might be practicable here since a spillway could perhaps be arranged over the low spur forming the left abutment. From this dam 40,000 g.p.h. pumps would deliver to Mudgee and 10,000 g.p.h. pumps would deliver to Gulgong.
Capital Cost is £282,000, and Annual Charges £14,193.
Green Gully Proposal.
System 'D'. Supply to Mudgee from Green Gully.
This is a proposal for a gravity supply from a 250 million gallon storage controlling 12.8 sq. miles of the Green Gully catchment area. The catchment is too small to provide supply to both Mudgee and Gulgong and it would be desirable to retain the existing well supply in Mudgee in order to take care of the possible shortages in the Green Gully supply during periods of prolonged drought.
An earth filled dam 48ft. high is contemplated with a spillway passing over the top of the fill. The gravitation main would comprise 16,000 ft. of 15" pipe to Queen's Pinch, whence 10,000 feet of 8" pipe would lead to a break pressure tank and thence 43,000 ft. of 10" pipe would supply to Mudgee.
Capital cost is £186,000 and annual charges £8,440.
Underground Source for Mudgee.
System 'E'. Supply to Mudgee from augmented underground sources.
In case of Mudgee, there is good prospect of drawing ample supply from the Burrundulla Flats. This could be arranged by sinking a series of bores across the flats extending easterly from the new bore These several bores could deliver to a small balance tank on the flat whence float controlled high lift pumps could supply 20,000 g.p.h. through the existing 8" rising main to Mudgee.
Alternatively, a single well could be sunk 40 or 50 feet deep about a quarter mile east of the new bore and equipped with 20,000 g.p.h pumps supplying direct to Mudgee This proposed well supply could then be an alternative to the new bore and they would not both be operated concurrently.
The existing system of four wells north of Mudgee could be reorganised by constructing a balance tank on the flat near No. 1 well and arranging necessary alterations to the existing pumps so that they would deliver to the balance tank. Each well pump would then have two float controls in series so that each would pump only when the water is required and available. High lift 20,000 g.p.h. pumps would be installed to deliver from this balance tank to the Mudgee Reservoir.
Tentatively assuming that a well at Burrundulla is adopted in preference to a series of bores the economics of this augmentation would be (approximately), capital cost £34,000; annual charges £2,507.
Underground Sources for Gulgong.
System 'F'. Supply to Gulgong from underground sources.
In the case of Gulgong the groundwater possibilities are rather less promising and considerable expenditure on exploratory boring and testing may be necessary before a satisfactory underground source is located.
To indicate the outlay that may be involved in such an augmentation, the following is a preliminary economic statement: Capital cost £17,000; annual charges for bulk supply £1,453.
For the sake of simplicity the estimates given above relate only to the cost of bulk supplies. In order to give the councils a clear understanding of the actual effect of any one of the possible augmentations upon its finances, I am attaching to this letter a number of schedules in which the estimates of economics are set out in greater detail. In this statement the actual cost of power is taken at the actual 2d. per kwh instead of the future 1¼d per kwh assumed above.
Although this investigation was carried out with the express purpose of locating satisfactory augmentations by means of a surface storage, it appears that all the possible surface supplies are rather expensive and that further explorations could be made into the possibility of augmented underground supplies.
In the case of the Mudgee Water Supply the Burrundulla flats could be further explored in order to survey the depth and extent of the underlying gravel drift. On completion of this exploration a decision could be reached as to whether development should be by a series of bores all pumped into a low level balance tank, or whether a large well should be sunk as provided for in the attached estimate. In reply to your letter dated 24th May, 1950, it is advised that the existing system could be improved to some extent as described above but that the Burrundulla flats offer the best prospect for augmentation.
It is thought that these comments together with the attached economic schedules should provide the Council with an adequate basis for a decision on this question, but I should be glad if you would, advise me further if any additional information is desired.
Gulgong: Supply From Cudgegong River Near Cullenbone.
Capital Cost is £66,000, and Total Revenue £3,571.
Gulgong: Supply From Ground Water Sources.
Total annual charges is £2,898 and Total Revenue £2,8552
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