Hydrogeology

PART A: Technical skills in hydrogeology

QUESTION 1

You are investigating an unconfined sand aquifer. The following data have been collected from a slug test of the aquifer, recording the depth to water in a monitoring bore before and after the slug was inserted into the bore:

The bore was made of PVC, with a screened interval from 9.50 to 11.0 m below the ground surface. The borehole has a diameter of 80mm. It can be assumed that the effective radius is the same as the borehole radius.

1. Calculate the Le/R value (and confirm it meets the criteria for using the Hvorslav method) as well as the h₀, h and h/h₀values for each time step. Write these in the table above in the appropriate places (4 marks)

Solution:-

Given:- Effective length of the well screen (Le) = 11-9.50m = 1.5m

Borehole Diameter = 80mm

Radius of the casing (r) = 40mm = 0.04m

Effective radius of the well screen (R) = 0.04m

1. Estimate the hydraulic conductivity of the aquifer in m/day, showing all working and using appropriate significant figures

Solution:-

Formula:-

K= Hydraulic conductivity

T₀ = 16.5 (from the above graph)

K= 8.847×10^-6 m/d

1. Explain any limitations associated with this method of estimating hydraulic conductivity (K), and name one alternative method to estimate K (3 marks)

Limitation: – The consequences of this assumption are explored here for the particular case of a well fully penetrating a confined, radially infinite, homogeneous, isotropic aquifer. The Cooper et al. (1967) model of this setting includes the effect of compressive storage and is otherwise identical to Hvorslev. Therefore, for this setting the performance of the Hvorslev method is gauged against that of the Cooper et al. model.

The alternative method to estimate K is laboratory methods and Field methods

Falling-head method

In the falling-head strategy, the dirt example is first soaked under a particular head condition. The water is then permitted to course through the dirt without including any water, so the weight head decays as water goes through the example. The advantage to the falling-head method is that it can be used for both fine-grained and coarse-grained soils.If the head drops from h i {\displaystyle h_{i}} hf to ∆t h f {\displaystyle h_{f}} in a time Δ t {\displaystyle \Delta t}, then the hydraulic conductivity is equal to

K = L Δ t ln ⁡ h f h i {\displaystyle K={\frac {L}{\Delta t}}\ln {\frac {h_{f}}{h_{i}}}}  

Two observation wells screened to the base of the same aquifer are located 3.2km apart horizontally. The ground surface at well A is 23.4m above the bottom of the aquifer, and at well B it is 10.2m above the bottom. The depth to water measured in well A is 10.5 m, and the depth to water in well B is 1.5 m. The top of the well casing is 0.5 m above ground at Well A and 0.9m above ground at Well B. The aquifer effective porosity can be assumed to be 40%.

1. Showing all working (including a sketch if necessary) calculate:
2. The hydraulic head at each well and flow direction between them
3. travel time for groundwater to flow between the wells

• the discharge per unit width of water through the unconfined aquifer

Given:-

Consider K = 3 x 10^-4 m/sec

L=3.2km = 3.2 x 10³ m

23. i) Hydraulic head at well A (hA) = 23.4m-10.5m = 12.9m

Hydraulic head at well B (hB) = 10.2m-1.5m = 8.7m

1. ii) Travel time for groundwater to flow between the wells

V= 6.12 / 2x x0.4×0.4

V=146.10 mins

           iii)

q’ = 3 x 10^-4 x 24 x 60 x 

q’ = 6.12 m²/d

1. Explain any assumption(s) in your answer to ii) above

(2 marks)

• The aquifer is homogenous.
• The aquifer is fully saturated.
• The aquifer is Isotropic.
• There is no change in the potential filed with times.
• The soil and water are incomresible.
• Flow is laminar and Darcys law is valid.
• All boundary conditions are known.

1. Is it realistic that flow would remain steady-state over the timescale you calculated in ii)?How would you check this?

No, it is not realistic that flow would remain steady- state over timescale. By using plot of radial distance vs drawdown time would check this.

1. Under what conditions (steady state or transient) are the aquifer properties transmissivity and storativity normally determined?

Transient Theis solution

Cross-sectional plot of transient Theis solution for radial distance vs drawdown over time

The Theis condition was made by Charles Vernon Theis (working for the US Geological Survey) in 1935,[1] from heat move writing (with the scientific assistance of C.I. Lubin), for two-dimensional spiral stream to a point source in an endless, homogeneous spring. It is basically

where s is the drawdown (change in water driven head at a point since the start of the test), u is a dimensionless time boundary, Q is the release (siphoning) pace of the well (volume isolated by time, or m³/s), T and S are the transmissivity and storativity of the spring around the well (m²/s and unitless, separately), r is the good ways from the siphoning great to where the drawdown was watched (m), t is the time since siphoning started (seconds), and W(u) is the “Well capacity” (called the exponential fundamental, E1, in non-hydrogeology writing). The well capacity is approximated by the interminable arrangements 

Commonly this condition is utilized to locate the normal T and S esteems close to a siphoning admirably, from drawdown information gathered during a spring test. This is a basic type of converse displaying, since the outcome (s) is estimated in the well, r, t, and Q are watched, and estimations of T and S which best imitate the deliberate information are placed into the condition until a best fit between the watched information and the expository arrangement is found.

1. If well A was pumped and the drawdown/time relationship in the well recorded, could the storativity be determined? Explain with reference to a relevant method/equation.

Yes storativity can be determined. Beacuse we have the values of b and Sy.

Storativity (S) = Coefficient describing amount of water released from an aquifer of thickness b per unit change in hydraulic head (pressure):

1. a) Unconfined aquifer (free drainage of porosity):

S = Sy + bSs Because Sy >> Ss;

S = Sy

1. b) Confined aquifer (de-pressurisation):

S = bSs

*In a Confined aquifer, porosity is generally not de-watered – aquifer remains saturated during pumping/loss of water.

*Confined aquifers can start to drain (like unconfined aquifers) if head drops below top of aquifer. If so, then S = Sy

QUESTION2 Coastal aquifers

1. Explain two different mechanisms that can lead to the occurrence of salt water in a freshwater coastal aquifer, including one natural process and one caused by human activity.

Saltwater interruption is the development of saline water into freshwater springs, which can prompt groundwater quality debasement, including drinking water sources, and different outcomes. Saltwater interruption can normally happen in beach front springs, inferable from the water powered association among groundwater and seawater. Since saline water has a higher mineral substance than freshwater, it is denser and has a higher water pressure. Thus, saltwater can push inland underneath the freshwater. Certain human exercises, particularly groundwater siphoning from seaside freshwater wells, have expanded saltwater interruption in numerous waterfront territories. Water extraction drops the degree of new groundwater, lessening its water pressure and permitting saltwater to stream further inland. Different supporters of saltwater interruption incorporate route channels or farming and seepage channels, which give courses to saltwater to move inland. Ocean level ascent could likewise add to saltwater intrusion. Saltwater interruption can likewise be intensified by extraordinary occasions like tropical storm floods.

Groundwater extraction

Groundwater extraction is the essential driver of saltwater interruption. Groundwater is the primary wellspring of savoring water numerous beach front territories of the United States, and extraction has expanded after some time. Under gauge conditions, the inland degree of saltwater is constrained by higher weight applied by the freshwater section, attributable to its higher rise. Groundwater extraction can bring down the degree of the freshwater table, decreasing the weight applied by the freshwater section and permitting the denser saltwater to move inland laterally. In Cape May, New Jersey, since the 1940s water withdrawals have brought groundwater levels by up down to 30 meters, lessening the water table to beneath ocean level and causing boundless interruption and defilement of water flexibly wells.

Groundwater extraction can likewise prompt well pollution by causing upwelling, or forthcoming, of saltwater from the profundities of the aquifer. Under benchmark conditions, a saltwater wedge broadens inland, underneath the freshwater in view of its higher thickness. Water flexibly wells situated over or close to the saltwater wedge can draw the saltwater upward, making a saltwater cone that may reach and pollute the well. A few springs are inclined towards this kind of interruption, for example, the Lower Floridan spring: however a moderately impermeable stone or earth layer isolates new groundwater from saltwater, segregated splits penetrate the limiting layer, advancing upward development of saltwater. Siphoning of groundwater fortifies this impact by bringing down the water table, diminishing the descending push of freshwater.

Channels and waste networks

The development of channels and waste systems can prompt saltwater interruption. Trenches give conductors to saltwater to be conveyed inland, as does the developing of existing directs for route purposes. In Sabine Lake Estuary in the Gulf of Mexico, enormous scope conduits have permitted saltwater to move into the lake, and upstream into the waterways taking care of the lake. Furthermore, divert digging in the encompassing wetlands to encourage oil and gas boring has caused land subsidence, further advancing inland saltwater movement.

Waste systems developed to deplete level seaside territories can prompt interruption by bringing down the freshwater table, lessening the water pressure applied by the freshwater section. Saltwater interruption in southeast Florida has happened to a great extent because of seepage channels incorporated between 1903 with the 1980s to deplete the Everglades for farming and urban turn of events. The primary driver of interruption was the bringing down of the water table, however the trenches likewise passed on seawater inland until the development of water control gates.

The common harmony among freshwater and saltwater in waterfront springs is upset by ground-water withdrawals and other human exercises that lower ground-water levels, diminish new ground-water stream to beach front waters, and at last reason saltwater to interfere seaside springs. In spite of the fact that ground-water siphoning is the essential driver of saltwater interruption along the Atlantic coast, bringing down of the water table by waste waterways has prompted saltwater interruption in a couple of areas, remarkably southeastern Florida. Other pressure driven burdens that decrease freshwater stream in beach front springs, for example, brought down paces of ground-water revive in sewered or urbanized regions, additionally could prompt saltwater interruption, yet the effect of such weights on saltwater interruption, in any event presently (2003), likely is little in contrast with siphoning and land waste.

The changeability of hydrogeologic settings, wellsprings of saline water, and history of ground-water withdrawals and freshwater waste along the Atlantic coast has brought about an assortment of methods of saltwater interruption over the locale. Saltwater can defile a freshwater spring through a few pathways, including parallel interruption from the sea; by upward interruption from more profound, progressively saline zones of a ground-water framework; and by descending interruption from beach front waters. A couple of these pathways are outlined on figures 21 and 22. A few creators have utilized the term saltwater infringement to allude to horizontal development of saltwater inside a spring and the term saltwater interruption to allude to vertical development of saltwater. This differentiation isn’t made in this report on the grounds that there are regularly both parallel and vertical segments to a specific saltwater-interruption issue, and in light of the fact that the net outcome—pollution of a freshwater spring—is the equivalent for either sort of saltwater development. Another term that has been utilized to portray a particular kind of vertical saltwater interruption is saltwater upconing, which alludes to the development of saltwater from a more profound saltwater zone upward into the freshwater zone in light of siphoning at a well or well field (Reilly and Goodman, 1987).

Saltwater interruption diminishes freshwater stockpiling in waterfront springs and can bring about the relinquishment of freshwater flexibly wells when groupings of broke up particles surpass drinking-water principles. Saltwater interruption has been archived all through the Atlantic beach front zone for over 100 years (Barlow and Wild, 2002), yet the level of saltwater interruption differs generally among territories and hydrogeologic settings. In numerous occurrences, the territory sullied by saltwater is restricted to little pieces of the spring and has almost no impact on wells siphoned for ground-water gracefully (Box C). In different cases, tainting is of territorial degree and has generously influenced ground-water supplies. For instance, in Cape May County, New Jersey, in excess of 120 flexibly wells have been relinquished since 1940 in light of saltwater tainting (Lacombe and Carleton, 1992). The degree of saltwater interruption into a spring relies upon a few elements, including the complete pace of ground water that is pulled back contrasted with the all out freshwater revive to the spring, the separation of the anxieties (wells and seepage waterways) from the source (or wellsprings) of saltwater, the geologic structure and conveyance of pressure driven properties of the spring, and the nearness of restricting units that may keep saltwater from moving vertically toward or inside the spring. Additionally, the time required for saltwater to travel through a spring and arrive at a siphoning admirably can be very long. Contingent upon the area and horizontal width of the progress zone, numerous years may go before a well that is unaffected by saltwater interruption out of nowhere may get tainted.

Figure 1. Schematic illustration of some of the modes of saltwater intrusion in a multilayer, regional aquifer system caused by ground-water pumping at wells. Saltwater moves into the unconfined aquifer from the Atlantic Ocean and into the shallow part of the top confined aquifer from the major bay. The two freshwater-saltwater interfaces at the seaward boundary of each of the confined aquifers also move landward as saltwater is drawn inland from offshore areas

1. For a groundwater sample with a radiocarbon activity of 36 pMC, estimate the groundwater ‘age’ (also called ‘residence time’). If it was found that the same water sample also contained a measurable concentration of tritium (e.g. >0.5TU) how would you explain this? Discuss with reference to theory of groundwater age distribution- using a sketch if necessary.

Romanticized groundwater age’ has been characterized above as the passed time since water entered the soaked zone. Nonetheless, examples of groundwater are limited in volume and contain exceptionally huge quantities of atoms. In a mass manner, groundwater moves in light of spatial slopes in liquid potential. Furthermore, in light of the fact that water is a liquid and the general places of particles are not fixed, those atoms move in irregular ways just as through mass stream. These likely determined and entropy driven vehicle forms cooperate in an intricate manner to deliver transport forms differently portrayed as ‘shift in weather conditions’, ‘dissemination’, ‘hydrodynamic scattering, etc (see Phillips and C astro (2003) [77] for a conversation of the impact of different vehicle forms on groundwater age tracers). One ramifications of groundwater transport is that the vehicle way of any individual atom of water may (and more likely than not does) contrast from the mean way got by averaging numerous particles. It is recognized that water atoms have a particular personality of the request for picoseconds; for this conversation, this idea is overlooked.) The outcome is that any limited estimated test of groundwater contains water particles that have lived in the framework for varying timeframes. This being the situation, a groundwater test at a particular area can’t be satisfactorily described by any single estimation ‘old enough’; rather, it is portrayed by a recurrence conveyance of ages.

The idea of liquid age characterized by a recurrence dispersion of ages was presented by D anckwerts (1953). From that point forward, it has been broadly applied in liquid elements, synthetic designing, climatic science, oceanography and hydrology (Hooper (2003) [79]; Loaiciga (2004) [80]; M cGuire and McDonnell (2006) [81]). In the compound building writing, the idea is by and large alluded to as the ‘home time appropriation work’. The habitation time dissemination is a scientifically thorough and for all intents and purposes helpful capacity (see references above for models).

FIG 2. A depiction of the role of dispersion in creating multipath routes from recharge to discharge in a 3-D groundwater system. Flow down the hydraulic head gradient produces decision points upon each encounter with the host grains of an aquifer. This probabilistic process creates dispersion in groundwater age arriving at position (Δx) downstream (Fig. 3.1(b)).

The conventional radiocarbon age, t, in years is, by definition:

Where,

τ is the Libby mean-life (5568 a/ln 2, where 5568 is the Libby half-life);

Ao is the initial 14C specific activity (in Bq/kg or mBq/g; 1 Bq = 1 disintegration per second);

A is the measured 14C specific activity.

By international convention, specific activities are compared to a standard activity, Aox, where

Aox = 0.95 times the specific activity of NBS oxalic acid (0.95 × 13.56 disintegrations per minute per gram of carbon (dpm/g C ) in the year 1950 A.D.). The initial 14C specific activity, Ao, and the measured 14C specific activity of a sample, A, can be expressed as a percentage of this standard activity in percent modern carbon (pmc) where pmc = (A/Aox) × 100 (Mook (1980) [109]).

Given :- 36 pmc

Therefore, the residence time (T) = 5568 ln 36

T=19,953.033 years.

Tritium is the radioactive isotope of hydrogen that has a half-life of 12.32 years. Environmental tritium in

precipitation has two sources. Natural tritium is produced by the interaction of cosmic radiation with atmospheric

gases. The second source is human-made and is derived principally from nuclear weapons testing and nuclear

reactors. 

Because of various meteorological processes, atmospheric moisture sources and local anthropogenic sources

(nuclear power plants, industrial sources, waste burning plants etc.), it generally is necessary to monitor or construct

a local record of ‘3H-in-precipitation’ for a particular region being studied.

Tritium is the radioactive isotope of hydrogen that has a half-life of 12.32 years. Environmental tritium in

precipitation has two sources. Natural tritium is produced by the interaction of cosmic radiation with atmospheric

gases. The second source is human-made and is derived principally from nuclear weapons testing and nuclear

reactors. 

Because of various meteorological processes, atmospheric moisture sources and local anthropogenic sources

(nuclear power plants, industrial sources, waste burning plants etc.), it generally is necessary to monitor or construct

a local record of ‘3H-in-precipitation’ for a particular region being studied.

Tritium is the radioactive isotope of hydrogen that has a half-life of 12.32 years. Environmental tritium in precipitation has two sources. Natural tritium is produced by the interaction of cosmic radiation with atmospheric gases. The second source is human-made and is derived principally from nuclear weapons testing and nuclear reactors.

Because of various meteorological processes, atmospheric moisture sources and local anthropogenic sources (nuclear power plants, industrial sources, waste burning plants etc.), it generally is necessary to monitor or construct a local record of ‘3H-in-precipitation’ for a particular region being studied.

Tritium is the radioactive isotope of hydrogen that has a half-life of 12.32 years. Environmental tritium in

precipitation has two sources. Natural tritium is produced by the interaction of cosmic radiation with atmospheric

gases. The second source is human-made and is derived principally from nuclear weapons testing and nuclear

reactors. 

Because of various meteorological processes, atmospheric moisture sources and local anthropogenic sources

(nuclear power plants, industrial sources, waste burning plants etc.), it generally is necessary to monitor or construct

a local record of ‘3H-in-precipitation’ for a particular region being studied.

Tritium is the only radioactive isotope whose behaviour is identical to that of water and ages estimated include the passage of the unsaturated zone as well. For this reason, the processes that will normally affect gas tracers, such as retardation, sorption and chemical processes and exchange with the atmosphere in the unsaturated zone have  practically no impact on tritium. In contrast to CFCs and 3H/3He-method,  3H-concentration is not changed in  contaminated (e.g. CH4, HS) reducing environments. In cases of mixing of modern water with old water, the  apparent age can be determined by the 14C, 39Ar and 81Kr techniques

QUESTION 3 Groundwater recharge

1. Describe three types of evidence or data which can be used to indicate the location(s), mechanism and rate(s) of groundwater recharge, using the Western Port Basin (southeast Melbourne) as an example(use specific data where possible)(6 marks)

Various revive contemplates including the utilization of electromagnetic enlistment meters were excluded from the past energize audits of Kennett-Smith et al. (1994), Petheram et al. (2000) and Petheram et al. (2002). Cook et al. (1989a) adjusted ground recurrence area electromagnetic (FEM) meters (Geonics EM31 and EM34) at 4 destinations (aggregate of 27 gaps) in the western Murray Basin in South Australia. These were utilized to infer hypothetical connections between electrical conductivity and the evaluated complete energize put away in the dirt profile to the profundity of each gap. Cook et al. (1989b) utilized the EM34 FEM meter aligned to revive rates assessed from chloride profiles (Figure 3-1) to examine the spatial inconstancy of energize in a 14 ha enclosure at Borrika with profound and moderately uniform sandy soils.

Figure 3. Theoretical relationship between apparent conductivity, determined using an EM34 ground conductivity meter, and recharge rate. Recharge rates determined from chloride profiles directly are compared. Arrows indicate minimum estimates using the transient chloride mass balance of soil water method (Figure 5 of Cook et al., 1989b)

Cook et al. (1992) contemplated revive along transects north of Borrika utilizing chloride profiles and both FEM (Geonics EM31, EM34, EM38, and EM39) and transient electromagnetic (TEM) meters. The electromagnetic meters were less effective in anticipating revive rates (Figure 3-2) around there as they were generally mapping soil type as opposed to the chloride draining profiles that were utilized to evaluate energize. Cook and Kilty (1992) stretched out this investigation to incorporate a multi-recurrence helicopter electromagnetic overview of a similar site. Relationships among’s energize and clear conductivity (Figure 3-3) were just huge (R2 = 65%) at the most elevated recurrence (56,000 Hz). It is obvious from these examinations that EM strategies scarcely work for uniform sandy soils thus they are unsatisfactory for progressively complex heavier finished soils. This is on the grounds that the dirt surface rules the clear conductivity as opposed to the chloride filtering profile which is utilized to evaluate saltiness and thus revive.

Figure 4. Comparison of field data relating apparent electrical conductivity to recharge and theoretical model. Model data are shown for 5, 10 and 20% clay contents. Cook et al., 1992).

1. Outline the major conclusions from the research study about the locations and rates of groundwater recharge in southeast Melbourne, and describe one major implication of these conclusions for the management of land-use in the area (4 marks)

There have been various profound waste/revive estimations made in South Australia. The significant investigation territories have been in the Western Murray Basin and the SouthEast, the two of which are sedimentary spring frameworks, and the cracked stone spring frameworks around Clare in the Flinders Ranges and in the Mt Lofty Ranges. The entirety of the South Australian examination zones have winter predominant precipitation atmospheres with mean yearly precipitation extending from 260 mm yr-1 in the Riverland (Western Murray Basin) to 660 mm yr-1 in the Green Triangle (South-East). The entirety of the energize/profound seepage estimations made preceding 1993 were remembered for the Kennett-Smith et al. (1994) audit and have shaped the premise of the post-clearing profound waste versus dirt substance relationship for the 300-399 mm yr-1 mean yearly precipitation regions. The later investigations examined in this segment present information and post-clearing profound waste versus mud content connections for lower and higher precipitation territories than those revealed by Kennett-Smith et al. (1994). A few of these examinations have assessed profound seepage as well as energize at a similar site utilizing around 4 distinct techniques (consistent state chloride mass equalization of soil water, transient chloride mass parity of soil water, chlorofluorocarbon or 14C groundwater dating and watertable change).

There has been countless revive estimations in the course of the most recent decade. a. We have recognized a sum of 4386 profound seepage as well as revive gauges from 172 examinations and these have been incorporated into an information base. b. Despite the size of the information base the spatial inclusion of energize assesses across Australia is inadequate and the thickness of studies is exceptionally factor, with certain districts (for example Mallee) all around spoke to though others (for example Gippsland) are totally ailing in any assessments. c. Cracked stone springs are ineffectively spoken to and this mirrors the troubles in assessing revive in these perplexing conditions.

PART B: Groundwater management

QUESTION 1

Coal seam gas companies have now established large scale production from the Walloon Coal Measures (WCM), part of the Surat Basin in south-east Queensland. The area also contains rich farmlands (the Darling Downs) as well as the important Condemned River. A conceptual diagram of the geology is shown in the cross section below.

Note: the blue upside-down triangles represent the approximate potentiometric surface (or water table) for the aquifers (with change in the Walloon Coal Measures before and during CSG labelled on the left hand side). The vertical scale from the surface to the base of the picture is approximately 400 m.

• Name three impacts from the coal seam gas extraction which may affect the groundwater and/or surface water. For each impact, indicate the affected receptor(s), and describe the mechanism by which it may occur, being as specific as possible (6 marks)

Ans: The coal crease extraction method impacts on water supplies in two fundamental manners: It requires enormous amounts of water at the siphoning stage and it is asserted to create immense measures of sullied groundwater containing synthetic concoctions referred to altogether as BTEX, methane gas and inordinate measures of salt. Attractors to this strategy for gas investigation and creation are twofold.

The boring procedure created and created by George Mitchell in 1980s and 1990s made penetrating already out of reach layers reachable and modest. The other fascination is that in the United States of America (USA), since 2008 the household cost of ‘Henry Hub’ gas has tumbled from $12 per million BTUs in 2008 to $4 per million BTUs in 2012. The effect of this 66 % fall in cost has diminished the USA’s dependence on imported carbon based fills vitally, however has deleteriously affected groundwater supplies.

Penetrating machine is utilized for coal crease extraction. Coal crease gas is held set up by water pressure. To extricate it, wells are bored through the coal creases and the water pressure is decreased by separating a portion of the water. This discharges flammable gas from the coal.

• Design a monitoring program by which you would protect the Condamine system from the impacts described above. In this you should include detail about which aquifer(s) and other features should be monitored, what type of data/measurements should be taken and the timing and frequency of these. Be sure to indicate which specific locations and depths are the most important to monitor, and justify this with reference to the conceptual geology above, and the type(s) of impacts noted in your answer to a) above (9 marks)

• At present, groundwater monitoring of CSG operations requires the use of ‘early warning triggers’, such as changes in groundwater levels or chemistry in particular monitoring bores. In your view, explain whether this approach is sufficient (or not) to protect the groundwater and surface water resources of the region from the impacts identified above? As part of your answer, be careful to explain how ‘early warning trigger’ values in a groundwater monitoring bore are expected to work in theory. (5 marks)

Ans:- Draft Exceedance Response Plans for situations are introduced at Appendix U and include:

• Response Plan I If Threshold Values for surface water quality and water ecological qualities are surpassed

• Response Plan ii If Early Warning, Threshold Values or Trigger Limits for spring drawdown corresponding to EPBC recorded springs are surpassed

• Response Plan iib Threshold Values for spring drawdown corresponding to groundwater-delivering exhausts are surpassed

• Response Plan iic Threshold Values for groundwater defilement are surpassed

• Response Plan iii Subsidence or surface misshapening happens which impacts on surface or groundwater hydrology.

Exceedance Response Plans will be enacted following the underlying notice to the Minister. Each Plan is worked around a two-staged Critical Review Process with answering to SEWPAC at key occasions (see Figure 43). Where essential, a Mitigation Plan would be recognized and executed as a different third stage. For each situation under Phase 1, a work area audit and composed report must be arranged and submitted to SEWPAC inside a designated number of days of the exceedance and address the accompanying:

• Verification of the exceedance. The confirmation procedure will rely upon the kind of exceedance. On account of a water quality exceedance this would at any rate include a re-examination of the example exceedance and (on account of a surface water exceedance) a resampling at the applicable release area.

• Processes that may have added to the exceedance. Affirm if there is a connect to CSG exercises. If not, exhort and close out.

• Likelihood of proceeded with exceedances moving forward without any more activity • Management choices to keep away from future exceedances

• Any extra observing required to affirm the noteworthiness and span of the exceedance

• Any different changes recorded by the important observing project

• Statement about possible consequences for the getting condition and the requirement for additional examination and evaluation.

Stage 2 is established where the finishes of the work area survey recognize an unsatisfactory danger of an unfriendly or noteworthy impact on the getting condition, or potentially SEWPAC additionally closes from the report that further examination is required. The time period for Phase 2 relies upon the particular exceedance yet could shift from three to a half year.

Stage 3 would include the usage of further alleviation measures. Explicit alleviation estimates will rely upon the kind of exceedance. Demonstrative alleviation measures for every exceedance type are laid out underneath.

QUESTION 2

Explain what is meant by ‘Cultural Flows’ and outline one case study/example of how Indigenous knowledge and cultural values can be incorporated into water management decisions, in accordance with the provisions in the National Water Initiative on Indigenous Access.

Ans :- The Indigenous people groups whose nation exists in the Murray-Darling River Basin, contend that they require explicit social water portions, which they allude to as social streams, to meet their profound, social, social, financial and natural administration obligations and advancement yearnings.

Indigenous qualities and investigate the use of techniques to determine water prerequisites to meet them. Members shared their water esteems with scientists who evaluated a constrained arrangement of water prerequisites important to continue those qualities and afterward surveyed whether these water necessities would be met under three elective water the executives situations, one of which would involve a generous reallocation of water to the earth.

The NWI states: The Parties will accommodate Indigenous access to water assets, as per pertinent Commonwealth, State and Territory enactment, through arranging forms that guarantee:

• inclusion of Indigenous portrayal in water arranging at every possible opportunity; and

1. ii) water plans will consolidate Indigenous social, profound and standard targets and methodologies for accomplishing these destinations any place they can be created.

Water arranging procedures will assess the conceivable presence of local title rights to water in the catchment or spring territory. The Parties note that plans may need to distribute water to local champions following the acknowledgment of local title rights in water under the Commonwealth Native Title Act 1993.

Water allotted to local champions for customary social purposes will be represented.

QUESTION 3 (8 marks)

The concept of sustainable yield is fundamental to groundwater management. For Victoria, explain how this concept is defined and applied in groundwater management. Provide an example where it has been applied and explain how it helped achieve sustainable groundwater management (or not,as the case may be).

Ans:- The expression “sustainable yield,” characterized by hydrologists as “the groundwater reflection system, estimated over a predetermined time period, that permits satisfactory degrees of stress and secures the higher worth uses that have a reliance on the water,” has been the essential idea controlling groundwater the board and strategy.

The reasonable utilization of groundwater relies upon sound administration rehearses. Given the expanding interest for this asset, the executives works on constraining access to, and extraction of, groundwater are essential. Successful checking is likewise required, to guarantee that entrance and extraction conditions are met.

Water companies oversee groundwater extraction from springs in topographical

regions known as groundwater the executives units. There are three sorts of

the executives units in Victoria :

• Water flexibly security territories—regions where there are intensely utilized

groundwater frameworks. They are dependent upon serious administration through

groundwater the executives plans.

• Groundwater the board regions—regions where groundwater frameworks have been seriously evolved or can possibly turn out to be all the more profoundly utilized. These regions may require an elevated level of the executives later on. All groundwater the executives territories are liable to water qualification tops and some are overseen through administration rules created and endorsed by water partnerships.

• Unincorporated territories—groundwater frameworks where there has been constrained turn of events or utilization of groundwater. This is normally on the grounds that the framework is low yielding, the water quality is poor and has constrained use, or there is restricted data about asset accessibility.

In Victoria Groundwater is generally utilized in excess of 40 urban areas and towns. Utilizations incorporate harvest water system, stock watering, dairy cleaning, local cultivating and cleaning. Towns likewise use groundwater for drinking where it has been dealt with. Irrigators, local and stock clients and urban occupants have depended all the more vigorously on groundwater during the dry season. Figure 1A shows that groundwater privileges and use have ascended over the five years to 2008–09, topping in 2006–07. This corresponded with the absolute most reduced precipitation on record. Figure 1B shows the correlation among groundwater and surface water use, and the expanded dependence on groundwater as the accessibility of surface water reduced.

QUESTION 4

Protecting groundwater quality is crucial in sustainable groundwater management. In recent years, contamination of groundwater with Per- and Poly-fluoroalkyl substances (PFAS) has been uncovered in Australian towns which use the water for drinking supplies.

• Name one site in Australia where PFAS contamination has been detected and outline how the problem is thought to have been caused (4 marks)

Ans :- Victoria is a site where the PFAS contamination were detected in Australia.

Per-and polyfluorinated alkyl substances (PFAS) are a large group of manufactured chemicals which have historically been used in firefighting foams and other industrial and consumer products for many decades. In one research they have found this all chemical in water of Victoria and they have come to know that there is PFAS is in Victoria ground water.

• You have been notified by a water authority that PFAS has been detected in groundwater used to supply a town in eastern Victoria. Explain how you would go about assessing and addressing the risk(s) to human health. In your answer be sure to explain/refer to:

Ans:- first ly we could educate all the residents that there is PFAS is recognized in their locale and that for our security district. They should take care there self before utilizing ground water and for the most part avoid potential risk for drinking water utilize just cleaned water of water froms channels for their postpone use.

The applicable arrangement on groundwater quality administration in Victoria

Insurance of groundwater quality happens inside three existing administrative systems:

• Groundwater Management, which manages groundwater privileges and portions

• Land-use Planning, which controls choices ashore advancement

• Environment Protection, which manages ecological upkeep and risky exercises

• The process by which groundwater contamination risks (including human health risk) should be assessed

Ans : Source-pathway-receptor-consequence (S-P-R-C) model is initially presented to explain the linkage between hazard and risk of flood. In risk management, the term “hazard” means an event that could cause harm, and the term “risk” is used to simply express the probability of something happening. Hazard is a physical event, phenomenon, or human activity with the potential to result in harm; it does not automatically lead to a harmful outcome, but identification of a hazard does mean that there is a possibility of harm occurrence.

• A possible management response to the risk, should it be deemed significant to warrant intervention.

 For this Gov. Of Australia have take some serious action against PFAS

They take below mention report from each site for current and running year

The Detailed Site Investigation Report

The Detailed Site Investigation Addendum Report

The Human Health Risk Assessment and Preliminary Ecological Risk Assessment Report