Bundled Mini-Piezometers - Cranbourne New Homes

BUNDLED MINI-PIEZOMETERS

     Bundled mini-piezometers are used for discrete vertical sampling of water quality and hydraulic head measurements in unconsolidated sands (Acworth, 2007). This method is particularly useful for sampling at 0.25 or 1 m intervals through the saline-fresh interface in coastal sands. These mini-piezometers can also be used with a manometer board for density head corrections in coastal aquifers at the fresh/saline interface.

     Several designs are possible with this method; however, bundles consisting of a number of flexible plastic tubes—8 mm outer diameter (OD), 5 mm inner diameter (ID)—attached to the outside of a stem made from 25-mm-plastic pipe (electrical conduit) have been successfully used (Acworth, 2007).

     When connected to a vacuum and manometer, the advantage of this method is that it can be used to derive a vertical profile of water quality and hydraulic head measurements. Purging and sampling volumes can be minimised with very small tubing and this can be constructed using readily available and cheap PVC tubing. However, this method is suitable only for shallow unconfined and sandy aquifers. It requires an experienced person to construct and install and is time consuming.

     Additional information on the bundled mini-piezometers construction and installation can be obtained from Acworth (2007).

Senior Consultant S J Builders Australia, Visit http://www.sjbuilders.com.au/
Cranbourne New Homes
Craigieburn  New Homes
Builders In Berwick

Bore construction - Melbourne Town Planning

BORE CONSTRUCTION:

     Monitoring bores need to be constructed to a high standard to ensure ongoing and reliable data is obtained over the life of the bore. A bore should be constructed in accordance to national construction standards defined in Minimum Construction Requirements for Water Bores in Australia (ARMCANZ, 2003).

     When constructing a bore (see Figure 3), the casing material will be determined by the required bore depth and monitoring requirements, including the type of contaminants to be monitored.
The following materials should be considered, based on what is to be monitored:

• PVC, stainless steel and Fiberglas are suitable for monitoring most organic substances
• PVC or Fiberglas is suitable for monitoring most inorganic substances, particularly in corrosive waters.

     Consideration should also be given to the selection of an appropriate casing diameter that will allow pumping  and monitoring equipment to be easily installed.

     The bore casing for a monitoring bore should have mechanical joints to avoid contamination by solvents such as PVC solvent cleaner and cement. Organic-based lubricants (such as hydrocarbons) should not be used on casing joints, drilling rods or equipment if sampling for organics is required.

     A gravel pack may be used to avoid situation when fine-grained aquifers are encountered. The bore annuls should be carefully and evenly filled to a level approximately one meter above the screened interval with a graded gravel pack. Screen and gravel pack intervals should not be installed across different geological units or water-bearing zones.

                         Figure : A typical water monitoring bore (adapted from ARMCANZ, 2003)

     A cement or bentonite seal at least one meter thick should be placed on top of the graded gravel pack to prevent water movement from the surface or between aquifers. A bentonite seal may be constructed using pellets inserted slowly down the annuls.

     Where there is a possibility that contaminants are present at high levels, or are known to exist, extreme care must be taken to avoid contamination of deeper aquifers. Bores must be constructed to avoid cross-contamination of aquifers. Particular care needs to be taken when positioning the screen as it can provide
a pathway between aquifers.

     All bores should be capped with a lockable cap to prevent ingress of surface water, dust or other foreign matter and to avoid tampering.

     The bore should be clearly labelled with the bore name or ID number.

     Additional information on bore construction requirements and standards can be obtained from the document Minimum construction requirements for water bores in Australia (ARMCANZ, 2003).

SHALLOW PIEZOMETER CONSTRUCTION AND INSTALLATION:

     Piezometers are shallow pipes used to monitor characteristics of an unconfined aquifer, generally within 5 m of the ground surface. Piezometers can be made easily from PVC pipe (Figure 4) and installed using an auger.The national minimum construction requirements for water bores (ARMCANZ, 2003) also provides information concerning small-diameter shallow piezometers. An example of a simple construction method is outlined below.

                                                                       

                                  Figure : Nested piezometer construction

1. Shallow piezometer construction:

1.1 Equipment:
The equipment you will need to construct a piezometer includes:

• 2–3 m of 50 or 80 mm diameter PVC pipe
• two 80 mm PVC caps
• saw

1.2 Procedure:
1. Dig test hole to determine the depth to groundwater, the piezometer should be 500 mm longer than the  depth to the water table.
2. Using the saw, cut small slots along the bottom 500 mm of the piezometer to allow the groundwater to  enter (see Figure 5).
3. Place a PVC cap over the bottom of the piezometer.

2. Shallow piezometer installation:

2.1 Equipment:
The equipment you will need to install a piezometer includes:

• auger (extendable to 5 m) with a 100 mm tip
• bucket of gravel or sand, with the typical grain-size dependent on the aquifer lithology
• bentonite pellets (pre-soaked)
• premixed concrete
• a capped galvanized or clay pipe (large enough to case the piezometer above the ground)
• extra PVC pipe and extension joint
• hacksaw

                                                         
                                            Figure : Cross section of a piezometer

2.2 Procedure:
1. Use the auger to dig a hole to the length of the prepared piezometer. The depth should be at least equal  to, but preferably greater than, the depth to the water table.
2. Put a small amount of gravel pack at the  bottom of the hole. Place the piezometer in the center of the  hole, ensuring that it extends at least 100 mm above the ground.
3. Fill around the pipe with the remaining gravel pack, to within 400 mm of
 the surface.
4. Fill the next 300 mm with a concrete/bentonite slurry, and the remainder with a concrete mix. Slope the  concrete so surface water flows away, reducing the likelihood of contamination of the piezometer with  surface water.
5. Place a larger diameter casing (typically PVC or galvanized iron) over the top
 of the piezometer to reduce the likelihood of damage.
6. Quite often when drilling or auguring holes, particularly in clay formations,he bore wall can become  smeared. To ensure the through-flow of groundwater it is recommended that the fully constructed bore is  pumped or bailed for a period immediately after construction and before it is used for monitoring.
 This will remove debris and fine material from the annuls.


Senior Consultant S J Builders Australia, Visit http://www.sjbuilders.com.au/
Melbourne Town Planning
New Homes In Berwick
New Homes In South Morang

Drilling and Bore Construction - Builders In Berwick

Drilling and Bore Construction:

     The simplest way to access groundwater is to dig a well. Wells can be dug manually to reach the shallow water table within the unconfined aquifer. However, if an aquifer is deeper than a few meters, a proper borehole needs to be drilled. Choosing a site, drilling method and bore construction are complex tasks requiring hydro geological knowledge, a skilled driller and specialized equipment.

     Many issues need careful consideration before a bore can be constructed. Some of the questions that need to be answered include (modified from Water watch, 2005):

• What is the geology and geomorphology of the area?
• How many aquifers exist, and which is the most appropriate one for the
 study purpose?
• How deep is the targeted aquifer?
• What is the purpose of the bore (monitoring, production, injection etc)?
• If it is a production bore, how much water is needed and how much water
 can reasonably be extracted?
• What are the licensing requirements and conditions operating within the
 State or Territory?
• Is there a groundwater management plan for the area?
• Are there any other bores in close proximity?
• Is the proposed location far enough from potential contamination sites like irrigation, septic tanks, drainage  lines, animal feedlots, etc.?
• If it is a monitoring bore, is it in a suitable position to monitor the impacts
 of potential contamination sites?
• Is the bore sited in an area where is could be prone to damage (such as by flooding, erosion, vandalism    etc)?
• Is the bore sited to minimise any disturbance or inconvenience to the land holder?
• Is the bore sited where there is infrastructure that is underground (such as
 water pipes, electrical cables, optical fibre networks) or overhead (such as
 power lines)?

     All groundwater bores should be drilled, cased and equipped according to national construction standards defined in Minimum Construction Requirements for Water Bores in Australia (ARMCANZ, 2003). This document deals with a broad scope of issues pertaining to water bore construction from licensing to construction, development and decommissioning for shallow small-diameter and low-yielding bores, through to high-yielding, deep and large-diameter bores.

 DRILLING METHODS:

     Drilling methods are many and varied, ranging from simple digging with hand tools to high speed drilling with sophisticated equipment. Each of the drilling methods has its advantages and disadvantages. The choice of drilling method employed should be made on the basis of geological and hydrogeological conditions and the type of facility to be constructed. The most commonly used drilling methods are described briefly below.
When selecting a drilling method or sampling an existing bore, the potential effects of the drilling method should be considered. Contamination of the borehole and its surrounds needs to be avoided during drilling and construction of the bore. Water contaminants, lubricants, oil, grease, solvents, coatings and corrodible materials may affect the suitability of the bore for groundwater monitoring, especially when monitoring for contaminants.

     All drilling and sampling equipment should be thoroughly cleaned before commencing drilling. Casing, drilling fluids and any materials used in the bore also need to be free of contaminants. Casing and screens should be kept in their protective covers until required for installation.

     There are many variations in methods used to drill monitoring bores. A driller experienced in the region being investigated can provide valuable advice on the best drilling method. The most common methods are described below with an overview of some of the issues that may affect the sampling of bores drilled using the technique. The selection of a drilling method and construction materials for a monitoring bore should take into account how these may influence analytes chosen for monitoring.

     When drilling a monitoring bore, a lithological log (and preferably a stratigraphic interpretation) should be made by an experienced person able to identify the important features.

1. Auger drilling:

      Auger drilling works on the simple mechanical clearing of a hole as it is drilled. Auger drilling eliminates the need for a drilling fluid (liquid or air) and hence reduces the potential influences from an introduced fluid. However, auger drilling has a high potential for smearing material such as clay or contaminants along the hole, thus affecting groundwater flow paths or increasing contaminant concentrations.

There are two major types of auger drilling:

• solid flight augers consisting of solid helical flights where extensions are added as the hole is drilled
• hollow flight augers consisting of augers that have a hollow centre.

     Auger drilling is generally used in soils and soft rock for relatively shallow bores.
It is possible to insert the casing into the hollow centre of a hollow flight auger before it is removed from the hole. This does require a large diameter borehole, but can be particularly useful in sandy ground.

2. Rotary air drilling:

     Rotary air drilling uses a rotating drill bit combined with circulating air that clears the drill cuttings, blowing them to the surface. The major advantage of rotary air drilling is that groundwater-bearing formations tend to be easily identified when encountered. The disadvantage of rotary air drilling is the potential for oxidation, volatilisation and precipitation of substances of interest. The introduction of high pressure air may also disturb flow paths and hydrochemical profiles in some aquifers.

3. Rotary mud drilling:

     Rotary mud drilling works on the same principle as rotary air drilling except that liquid is used as a circulation medium. Mud additives are used to support an open hole in soft and unconsolidated formations. The use of liquid may influence the formation, and hence groundwater samples, in the following ways:

• drilling fluids may enter the aquifer and mix with groundwater
• clay particles or other chemical products in the drilling mud may sorb or chemically alter the groundwater    properties
• mud may restrict or block groundwater flow paths.

4. Cable tool drilling:

     Cable tool drilling involves lifting and dropping a string of drilling rods with a bit at the base that cuts the hole with each blow. The cuttings are retrieved by removing the drilling rods and collected using a bailer. Cable tool drilling is slow and can compact aquifer material around the hole.

5. Direct push technology:

     Direct push (DP) technologies are an alternative method to conventional drilling techniques for sampling groundwater and installing monitoring bores in unconsolidated materials such as clay, silt, sand, and gravel. They are appropriate for sampling in the saturated zone and to depths of around 20m. Typically, a truck mounted mechanical hammer or hydraulic rig is used to push a string of steel hollow rods or a drive casing to the desired depth with a sacrificial tip. The rod assembly is disengaged from the tip and the sampling screen exposed. By directly pushing the sampler, the soil is displaced and helps to form an annular seal above the sampling zone. Direct push technologies are generally faster to install and more economical for high density sampling. They produce little or no cuttings during installation. DP installed groundwater bores are not appropriate for high volume sampling, are not recommended when telescoped bores are required to prevent migration of contaminants below confining layers, and may not penetrate hard bands, bedrock
and some unconfined layers (US EPA, 2005; ASTM, 2005).

6. Sonic drilling:

     Sonic drilling is a relatively new technique, where a high frequency vibration is combined with rotation to advance the drill stem. The core barrel is retrieved and the sample vibrated into a plastic sleeve or core trays. The advantage of this technique is relatively continuous and undisturbed geological samples, without the use of drilling fluids or other potential contaminants.

7. Vibro coring:

     Vibro coring method is used wherever soil conditions are unsuited to gravity corers or where greater penetration of the seabed is necessary. Standard size vibro coring equipment will produce 86 mm diameter core samples to a maximum depth of 6 m. In coarse aggregates larger diameters up to 150 mm can be obtained. This method is used widely throughout the geotechnical investigation industry and ca be deployed in water depths up to 1000 m.

Senior Consultant S J Builders Australia,Visit http://www.sjbuilders.com.au/

Builders in cranbourne
Builders in craigieburn
Builders in berwick

Designing a Groundwater Sampling Plan - Craigieburn New Homes

SAMPLING PLAN

   It is important to prepare a good sampling plan. The plan will describe where, what, why, how and when you will be sampling, and who will be doing it. The sampling plan should be prepared in consultation with stakeholders and field and laboratory technicians. The main steps associated with groundwater sampling are presented in Figure 2, and such planning is the first step in this workflow.

   When designing a monitoring or sampling plan, issues of possible hazards as well as standard behaviour at the sampling site should be considered. By observing basic safety rules you will minimise the risk of accidents and ensure safety of the members of your sampling group.

   Build your groundwater sampling plan around the following questions (modified from Waterwatch (2005)).

• Why are you field sampling?
• Who will use your data?
• How will the data be used?
• How will the data be achieved?
• What will you sample?
• What data quality do you require?
• What methods will you use?
• Where will you sample?
• How will the sample be preserved?
• When and how often will you sample?
• Who will be involved and how?
• How will the data be managed and reported?
• How will you ensure your data are credible?
• What potential hazards are there associated with the sampling?
• How can these hazards be mitigated?

CRITERIA FOR SAMPLING

   Existing bores in a study area largely define the potential sites for groundwater sampling, however natural features (such as springs) or artificial features (such as mine shafts or pits) can also be used for groundwater access. It is a common practice to sample surface water bodies and rainfall to integrate with the groundwater chemistry. Different criteria can determine which bores are to be sampled, including the:

• spatial and depth distribution allowing reasonable representation across and within the target aquifer(s)
• spatial distribution to allow development of cross sections parallel and perpendicular to regional  groundwater flow paths
• depth to water level ranging from shallow to deep groundwater systems (including perched and multiple  aquifers). Some nested or multi-stemmed piezometers may need to be sampled to investigate chemical  variations with depth (from the shallow watertable aquifer to deeper confined systems)
 at a site
• representation of the various land uses covering broad acre agriculture, various crops types, irrigation  practices, industrial or urban areas. Sampling needs to be carried out to address the groundwater  contamination potential with particular reference to nutrients, pathogens and pesticides
• representation of sampling to describe the recharge and nature and extent
 of groundwater/surface water interaction. Hence, bores may be selected on
 the basis of being close to surface water sites (such as streams, lakes, wetlands and estuaries)
• representation of the diversity of groundwater use in the area, including irrigation, stock, domestic and town  water supply, and
• logistical issues that define bore accessibility, such as bore ownership, operating condition, road access and  the existence and nature of bore equipment (such as an installed pump).

FREQUENCY AND DURATION OF SAMPLING

   The frequency and duration of groundwater sampling (Table 2) is an important issue that should be considered when designing a sampling plan. For example, if the monitoring is for a basic groundwater resource assessment it is recommended quarterly sampling for groundwater levels, annual sampling for basic quality indicators (e.g., electrical conductivity (EC) and temperature (T)) and as-need basis for other quality parameters (Table 2). Collection of long-term (one or more decades) water level data is recommended for better understating issues associated with groundwater availability and sustainability (USGS, 2001).

Table : Indicative monitoring frequency for various groundwater monitoring purposes (adapted from
              Timms et al., 2009).

PURPOSE FOR MONITORING GROUNDWATER LEVEL GROUNDWATER QUALITY INDICATOR (e.g., EC, T) GROUNDWATER QUALITY PARAMETERS** Basic Resource Monitoring Quarterly Annual As required Resource Monitoring at Sensitive Sites (eg. Significant Drawdown, Well Head Protection Zone, Risk of Groundwater Quality Impacts) Daily Monthly Quarterly Recharge Processes & Rainfall Response Daily or Hourly Monthly or Hourly As required Measure Aquifer Confinement and Specific Storage Hourly or 15 minute* - - Point Source Contamination – Potential Impacts^ Quarterly Quarterly Half-yearly Diffuse Source Contamination – Potential Impacts Half-yearly Half-yearly Annual

* Including barometric pressure measurement at the bore site, # NSW Groundwater Quality Protection    Policy,
^ Depending on Groundwater Quality Protection Level.
** Selection of appropriate water quality parameters for testing depends on the purpose of monitoring, possible contaminants and constraints on the cost of analyses.

                         Figure : Steps in groundwater sampling


Senior Consultant S J Builders Australia,Visit http://www.sjbuilders.com.au/

Craigieburn New Homes
Builders In Berwick
Builders In South Morang

National Water Quality Guidelines - new homes in berwick

NATIONAL WATER QUALITY GUIDELINES:

    The current national water quality guidelines for drinking water (ADWG, 2004) and irrigation, livestock watering and aquatic ecosystems (ANZECC/ARMCANZ, 2000) provide a critical framework for regulators, managers, researchers and the community. The national guidelines are summarised in Table 1. The guidelines place specific thresholds on the quality of water that is intended for specific uses. The goal of groundwater protection is to protect the groundwater resources of the nation so that these resources can support their identified beneficial uses and values in an economically, socially, and environmentally sustainable and acceptable manner.

   Guideline values have been determined for those chemical components that are considered to have significant potential to harm human health at concentrations above the specified limits. Guideline values should not be exceeded in public water supplies. It should also be noted that exceeding the guideline values may not always be a matter for immediate concern, but rather a trigger for follow-up action.

   In many regions groundwater is used mostly for agriculture. The quality of groundwater is then assessed relative to guidelines established for livestock and irrigation. Since different crops and livestock vary considerably in their ability to tolerate salts in water, the major characteristic to be considered for water intended for use in agriculture is salinity and sodicity. Water quality guidelines for aquatic ecosystems also apply to groundwater. Guideline trigger values have been established for selected indicators. For some indicators, trigger values are based on alternative levels of species protection.

Table 1 : Australian Guidelines for Drinking Watera, Livestockb and Irrigation Waterb

PARAMETER	DRINKING WATER (mg/L)				LIVESTOCK WATERING		IRRIGATION LTVd		IRRIGATION STVe
HEALTH		AESTHETIC		(mg/L)		(mg/L)		(mg/L)
Thermotolerant coliforms	0 CFU/100 mL		-		100 CFU/100 mL		<10-10000 data-blogger-escaped-cfu="" data-blogger-escaped-ml="" data-blogger-escaped-span="">
Aluminium	NAD		0.2		5		5		20
Antimony	0.003		-		-		-		-
Arsenic	0.007		-		0.5-5c		0.1		2
Barium	0.7		-		-		-		-
Beryllium	NAD		NAD		-		0.1		0.5
Boron	4		-		5		0.5		Crop dependent
Calcium	-		-		1000		-		-
Cadmium	0.002		-		0.01		0.01		0.05
Chloride	-		250		-		Crop dependent		Crop dependent
Chromium (as VI)	0.05		-		1		0.1		1
Cobalt	-		-		1		0.05		0.1
Copper	2		1		0.4 (sheep) 1 (cattle) 5 (pigs/poultry)		0.2		5
Fluoride	1.5		-		2.0		1.0		2.0
Iodide	0.1		-		-		-		-
Iron	-		0.3		-		0.2		10
Lead	0.01		-		0.1		2		5
Lithium		-		-		-		2.5 (0.075 on citrus)
Magnesium	-		-		-		-		-
Manganese	0.5		0.1		-		0.2		10
Mercury	0.001		-		0.002		0.002		0.002
Molybdenum	0.05		-		0.15		0.01		0.05

PARAMETER	DRINKING WATER (mg/L)				LIVESTOCK WATERING		IRRIGATION LTVd		IRRIGATION STVe
HEALTH		AESTHETIC		(mg/L)		(mg/L)		(mg/L)
Nickel	0.02		-		1		0.2		2
Selenium	0.01		-		0.02		0.02		0.05
Silver	0.1		-		-		-		-
Sodium	-		180		-		Crop dependent		Crop dependent
Uranium	0.02		-		0.2		0.01		0.1
Vanadium	-		-		-		0.1		0.5
Zinc	-		3		20		2		5
Ammonia (as N)	-		0.41		-		-		-
Nitrite (as N)	0.9		-		9.12		-		-
Nitrate (as N)	11.3		-		90.3		-		-
pH		-		6.5-8.5		-		6-8.5
Sulfate	500		250		1000		-		-
TDS	-		500		Stock dependent		Site specific		Site specific

a From Australian Drinking Water Guidelines, National Water Quality Management Strategy,    NHMRC/NRMMC, 2004.
b From Australian and New Zealand Guidelines for Fresh and Marine Water Quality,  ANZECC/ARMCANZ, 2000.
c May be tolerated if not provided as a food additive and natural levels in the diet are low.
d LTV denotes long-term trigger value, the maximum concentration of contaminant in the irrigation water that  can be tolerated assuming 100 years of irrigation, based on irrigation loading assumptions.
e STV denotes short-term trigger value, the maximum concentration of contaminant in the irrigation water  which can be tolerated for a shorter period of time (20 years), assuming the same maximum annual irrigation  loading to soil as for the LTV.
 NAD denotes No Available Data.


Liya,Senior consultant in S J Builders Australia. Visit http://www.sjbuilders.com.au/,

new homes in berwick
new homes in south morang
cranbourne new homes