course 3: water quality monitoring and assessment

Course 3: Water Quality Monitoring and Assessment

UNESCO-IHE Institute for Water Education Course 3 OLC Water Quality Assessment


Course 3: Water Quality Monitoring and Assessment

Table of Contents

Unit 1 Concepts of monitoring and assessment

Unit 2 River basin monitoring

Unit 3 Lakes and reservoirs

Unit 4 Water Quality variables

Unit 5 Monitoring frequencies and Optimization

Unit 6 Field and laboratory work

Unit 7 Water quality assessment and reporting

Unit 8 Groundwater monitoring

Unit 9 Cost aspects


Unit 1 – Concepts of monitoring and assessment In this unit we will give a short overview of:

1. Different types of monitoring, in relation to the set objectives 2. Components of a typical monitoring cycle

A good overview can be found in Chapter 2 of the book of Chapman (1996). Below (and in the Power Points) follows a reduced version. 1.1. Definitions and types of monitoring Water quality monitoring can be defined as “the programmed process of sampling, measurement and recording of various water characteristics, often with the aim of assessing conformity to specified objectives”. Various objectives can be listed for carrying out water quality monitoring such as: Type of monitoring Objectives

Ambient monitoring - Status and trend detection - Testing of water quality standards - Calculation of loads

Effluent monitoring - Calculation and control of discharge standards - Monitoring of plant performance

Early warning - Warning for calamities - Protection of downstream functions

Operational monitoring - Monitoring for operational uses such as irrigation, industrial use, inlets for water treatment works.

The design of a monitoring network will highly depend on above objectives of the programme. In this way, only the essential data is collected and needless waste of money, effort and time is avoided. Furthermore, periodical evaluation of the monitoring programmes is essential, to check whether the objectives are still met. Exercise (see answers at the end of this Unit): Categorise the following statements concerning information needs, into the different types of monitoring networks given above: • I want to know if, last year, the swimming water in Europe has been up to standard • Does the industry live up to their permits? • Can this water be used for irrigation? • Can the water companies downstream the river safely take in water in the coming

days? • Has the water quality of this lake been improved this year, compared to last year?


One can distinguish three levels of monitoring: • Simple monitoring, based on a limited number of samples, simple analysis or

observations, and data treatment which can be performed by simple software programmes

• Intermediate-level monitoring, requiring more variables, stations, and specific laboratory equipment and PCs for data handling

• Advanced level monitoring, involving sophisticated techniques and highly trained technicians and engineers for sample analysis (e.g. micropollutants) and data handling, often using mainframe computer systems.

Not every laboratory can perform all analyses; it is better then to involve "Central labs". In the following, an overview will be given on the design of monitoring programmes in surface waters, on site selection, monitoring frequency and parameters, etc. 1.2. The monitoring cycle Over the last decades, much attention has been given to the various factors that determine a successful water quality monitoring programme. Useful information can be found in specialised handbooks, e.g. Chapman, 1996, and in (downloadable): Bartram, J. & R. Balance (eds.), 1996. Water quality monitoring. Chapman & Hall, New York, 383 pp. (http://www.who.int/water_sanitation_health/resourcesquality/wqmonitor/en/ Fig. 1 shows the water quality monitoring cycle. In the following chapters, the various stages in this monitoring cycle will be highlighted.

Fig. 1. The monitoring cycle Meybeck, 1992, in Chapman (1996) defined ten basic rules for successful water quality assessment: 1. Clear objectives, in line with the available resources; 2. A clear understanding of the water body, by preliminary surveys; 3. A choice of the appropriate media (water, sediment, biota);


4. A choice of parameters, stations and frequency, etc. in line with the objectives; 5. A choice of methods, instruments, laboratory facilities, etc. in line with the

objectives; 6. A good reporting scheme; 7. Integration of water quality and hydrological monitoring; 8. A good Quality Assurance and Control (QA/QC) programme; 9. Clear recommendations to the decision makers; 10. A regular evaluation of the monitoring programme. Although not specifically mentioned by Meybeck, also the available recources (funds, manpower, training, facilities, etc.) must always be taken into account as well. The design of a monitoring programme should be based on clear and well thought-out aims and objectives and should ensure, as much as possible, that the planned monitoring activities are practicable and that the objectives of the programme will be met. The design of a water quality monitoring programme, the selection of sampling stations, the frequency of sampling, the parameters to be analysed, etc. all depend greatly on the objectives of the programme. No monitoring programme should therefore be started without defining these objectives; also they should be evaluated regularly! When a new programme is being started, it is very useful to begin with a survey of the region. The duration of such surveys will be between a few months up to a year, and should preferably include the different seasons. Of course, much information can already be derived from previous, historical monitoring data. In the survey, insight can be acquired on the general water quality characteristics of the region and variations herein, the different pollution sources, and on the hydrological variables. Assumptions on representativeness of stations, of mixing regimes in rivers, etc. can be tested. The survey period is of great value for the field and laboratory workers for gaining experience and fine-tuning of the procedures for sampling, storage and analysis of samples. They can also help to refine the logistical aspects of monitoring, such as difficulties in transport and accessibility. A description should be made of the monitoring area, with at least:

- Definition of the area, and schematisation in clear, not-overloaded maps - A summary of the environmental conditions and processes, including human

activities, such as population, land use, industries, hydraulic structures, (ground)water extraction sites and recreational areas;

- Meteorological and hydrological information, including hydrographs of river flows, and precipitation/evaporation data at stations as close as possible to the water course;

- A summary of actual and potential water uses. Fig. 2 shows a schematic representation of the water balance of a lake as an example output while describing the monitoring area. An example of a pollutant source inventory is presented in Fig. 3, for the watershed of Lake Vättern in Sweden. The emphasis is put here on water uses and their specific water quality requirements, particularly in the future. Economic trends should be


predicted for at least five years ahead since monitoring design; implementation and data interpretation take a long time. It cannot be over-emphasised that the benefits for an optimal monitoring operation, drawn for careful preliminary planning and investigation, by far outweigh the efforts spent during this initial phase. Mistakes and over-sights during this part of the programme may lead to costly deficiencies, or overspending, during many years of routine monitoring!

Fig. 2. (left) Schematic representation of the water balance of a lake

Fig. 3. (right) Pollutant source inventory for the Lake Vättern basin, Sweden (Chapman, 1996) Action List for Unit 1 • (Answers for exercise in Ch. 1.1.: ambient; effluent; operational; early warning;

ambient) • Look and listen to the PowerPoint presentation available under “Lecture”. • Read Chapter 2 in Chapman (1996).

Unit 2 – River basin monitoring In this Unit we will have a look at rivers - their definition, special characteristics, why it is important to monitor them, and how to do this. 2.1. General characteristics of rivers 2.1.1. Overview Rivers are lotic or flowing water environments and by themselves are confined to a channel or riverbed, but they receive water from a large area which is called a


catchment, watershed or river basin. Rivers can have different morphometries, i.e. geometric looks. They can form straight channels, like they do in mountain areas, or be strongly meandering and braiding, such as in floodplains. Streams consist of clear water flowing over shallow gravel riffles separated by deeper pools that collect organic debris. Rivers are muddier, larger and deeper and usually lack riffles and pools. There are three main types of streams: - Ephemeral streams regularly exist for short periods of time, usually during a rainy

period, and may have defined channels even when they are dry. - Intermittent streams flow at different times of the year, or seasonally, when there is

enough water from rainfall, springs, or other surface sources such as melting snow or even discharge from a wastewater treatment facility.

- Perennial streams are those that flow year-round. Below you can find an example on one of the most important perennial rivers in Africa: The Okavango River and Delta The Okavango River (Namibia & Botswana) is the only perennial river in Africa that flows eastward without reaching the ocean. Instead, it empties onto the sands of the Kalahari Desert, irrigating 15,000 km² of the desert. Each year some 11 cubic kilometres of water reach the delta. The area of the Okavango Delta fluctuates between 6,000 to 8,000 square kilometres during the dry season, swelling to 15,850 square km during the flood. Over 150,000 islands dot the Delta, varying in size from several metres to 10 km. The waters of the Okavango Delta are subject to seasonal flooding, which begins about mid-summer in the north and six months later in the south (May/June). The water from the delta is evaporated relatively rapidly by the high temperatures, resulting in a cycle of cresting and dropping water in the south. Islands can disappear completely during the peak flood, then reappear at the end of the season.

2.1.2. Physical parameters Streams may originate in two ways, either flowing from headwaters such as lakes, or from springs or groundwater seepage. The direction of stream flow is dependent upon the slope and obstructions of the landscape. Flow velocity is also determined by the


associated land gradient, which, when steep, not only speeds flow, but also increases sediment load and deposition. Rivers and streams, with flowing water, will create currents within the stream or river that wear away the sides of the channel, slowly shaping it over time. Currents are also responsible for moving and mixing organic and chemical substances as they enter the water through erosion and transport through weather (precipitation and wind) and animals (e.g. birds dropping seeds and plant matter). For a river system, physical parameters include: • Stream velocity or current, where one is interested in the rate of particle transport in

a certain direction. Due to turbulent flows of water, the measuring exercise can sometimes be tricky.

• Underlying geology: provides substrate sizes from silt to boulders. This influences the amount and type of benthic biota (fist-size stones provide the most favourable habitat for algae and invertebrates).

- Soft/acid-water streams flow over hard granitic, slate or sandstone which release only few nutrients

- Hard-water streams on limestone or sedimentary rock.

• The gradient of the water which is defined as the drop in elevation over a given stretch of flow. This is given by the topographical make up of the area in which the river is situated, i.e. steeper gradients in mountains than in lowlands.

• The cross-sectional area is usually a rough estimate, by using the width and depth at right angles of the flow direction.

• Another important feature is the discharge rate, i.e. how much water is being transported at one point in a certain unit of time. This is assessed by multiplying the average velocity by the cross sectional area and is usually measured in m3/s. High discharge moments are flood events.

• Riparian vegetation: the amount, type, height of the riparian vegetation affects the river temperature per se as well as the diel variations, organic matter input, etc.

2.1.3. Concept of river continuum

This concept was developed in the 1980’s for North American streams (so only partially true for other regions) and describes how energy flows change with stream order (see Fig. 4). First order stream, so small ones with no input except from runoff, will be narrow and shaded by trees with a large amount for nutrients coming from the detritus of falling leaves, etc., so allochtonous (external) production. Higher order streams will be wider and allow sunlight to penetrate, thus allowing for autochtonous (own or internal) energy production. Subsequently, this concept also divides benthic organisms into different types of consumers: shredders in the first order streams that chew on leaf and branch parts; scrapers, that remove biota (also called Aufwuchs) from macrophytes and will be found in the intermediate areas; and collectors, which are the filter feeders that take up the very fine particles of the large river beds.


Fig. 4 River continuum concept Stream order is also associated to the Strahler number, where a higher number is associated with increased branching. Only when streams with the same Strahler number merge, a higher number is assigned; in all other cases the highest number is retained (see below figure).

2.2. Monitoring After having set the objectives of the monitoring (e.g. trend monitoring, early warning) the selection of sampling stations can be differentiated into: • The macrolocation of the stations such as:

- Background or baseline stations - State/district boundaries - Impacts of major pollution loads (cities, industries, irrigation areas, etc.) - Recreational areas.

• Microlocation, defining the exact position of the monitoring sites:

- Usually after complete mixing of the river - Sites with guaranteed accessibility (e.g. at bridges).

Processes affecting water quality and their influence should be taken into account when monitoring stations are selected. Monitoring stations of rivers should be established at places where the water is sufficiently well mixed after a discharge (ranging from a few 100 metres for narrow brooks to > 10 km for wide rivers, see figure below; see Bartram and Balance, 1996). A bridge can be an excellent place for a sampling station: it is easily accessible and, often, a bridge is a hydrological gauging station (however make sure that you sample UPSTREAM of the bridge). As mentioned before, it is essential that water discharge and water quality parameters are measured simultaneously, because they are often interrelated. The spatial distribution of water quality stations within a river basin must be chosen in relation to the monitoring objectives, the expected variations, and the overall resources. Certain objectives, such as for compliance towards potable water supply extraction, require samples for concentration measurements, whereas others, e.g. for protection


of downstream lakes, require loads (discharge x concentration) assessments as well. In the latter case, a single station at the mouth of the river may be sufficient. Fig. 5. Left: Mixing patterns in a river; Right: Water discharges vs. ortho-phosphate (filtered) and PCB concentrations (unfiltered samples) in the river Seine, France (from Chapman, 1996). Note that for the latter component, increased discharges sometimes are related with increased PCB concentrations. (Sept.-Dec; why?) The location of sampling stations (Fig. 6) should be immediately upstream and downstream of major confluences and water use regions (e.g. urban centres, agricultural areas including irrigation zones, and industrial complexes). Also, monitoring stations should be located at national, state or municipal boundaries, generally put: at the boundaries for the regions of water quality monitoring authorities. As can be seen in Fig. 6, the sites also include “base line” or background stations, and “impact stations”.

Fig.6. Selection of monitoring sites in rivers (distance border-sea ~ 40 km)


Summarizing for Fig. 6, and using the earlier defined monitoring types : • Station #1 at the border (ambient + early warning); since the neighbouring

country or district will also have a monitoring station here, these may be combined, if possible (e.g. left/right bank, as in the Netherland/Germany border on the river Rhine).

• Station #2, for intake drinking water (operational station for drinking water company; the water quality will be very similar to that of station #1). Also (an) ambient/effluent station(s) downstream of the city

• Ambient station(s), e.g. #3, in recreational area (lake).The number of stations will, for example, depend on size and homogeneity of the lake (see Course 3.3.).

• An operational station #4, managed by the "Irrigation Authority". Also (a) groundwater station(s) may be needed, for impact of the irrigation area (see Course 3.8., on groundwater monitoring).

• Ambient station #5 for monitoring seawater intrusion • Any case one ambient station #6 upstream of an industrial area, and one

downstream, #7 (see hereafter). Effluent monitoring is needed for each industry. • "Background" or "baseline" station(s) downstream of unaffected area(s).

The choice of stations for the industrial area deserves critical attention. It should be avoided that new monitoring sites have to be selected for every new impact (e.g. new industry) in the watershed. Instead, industries can be obliged to monitor their effluents themselves, of course under strict enforcement and control by the regulatory body. Self-monitoring can be of the discharger’s own interest; it will provide valuable information to the industries about production efficiencies and ways to reduce spillage. The discharge permit can regulate the maximum amount of pollutants' discharges, related with the presence of other discharges and with the water quality standards for the receiving water body. This practice of emission control (effluents), together with immision control (water quality) has been a successful procedure in the Netherlands. As mentioned before, it will take many kilometres for complete mixing of the river and discharge water of the industrial zone. This "non-mixed" behaviour can in fact beneficially be used by monitoring the left and right bank (and middle, as "intermediate") of the river. Since each polluter has its own "fingerprint" (organic micropollutants; BOD, ammonia and phosphate; E-coli; heavy metals, etc.) it will be possible to monitor the individual polluters by using one ambient monitoring station, directly (e.g. 10 km.) downstream of the industrial zone; see PowerPoint lecture 3.2. Due to optimisation of water quality monitoring, e.g. by statistical evaluation, the number of monitoring stations in the Dutch surface waters has largely been reduced over the last decades (see PowerPoint lecture 3.2.); see also Course 4. Action List for Unit 2 • Look and listen to the PowerPoint presentation available under “Lecture”. • Read chapter 6 in Chapman (1996) Further Reading

• Book of Bartram and Balance (1996). Water quality monitoring; see Ch. 1.2. • In additional materials: Proceedings of "Conferences Tailor Made 1-4", texts

on "WISE" and on the "European Union Water Framework Directive."


Unit 3 – Lakes and reservoirs 3.1. Characteristics 3.1.1. Origins Most lakes on the surface of the Earth are fresh water and most are in the Northern Hemisphere. More than 60% of the lakes of the world are in Canada. Finland is known as The Land of the Thousand Lakes, having 187,888 lakes. Many lakes/reservoirs are man-made and are built to produce electricity, for recreation, to use the water in the industry, farming, or in houses. In this unit we will have a look at general characteristics of lakes, their importance and several aspects of monitoring. There are a number of natural processes that can form lakes. A recent tectonic uplift of a mountain range can create bowl-shaped depressions that accumulate water and form lakes. The advance and retreat of glaciers can scrape depressions in the surface where water accumulates; such lakes are common in Scandinavia, Patagonia, Siberia, and Canada. The most notable examples are probably the Great Lakes of North America. Lakes can also form by means of landslides or by glacial blockages. Salt lakes (also called saline lakes) can form where there is no natural outlet or where the water evaporates rapidly and the drainage surface of the water table has a higher-than-normal salt content. Examples of salt lakes include Great Salt Lake, the Aral Sea, and the Dead Sea. For the Aral Sea (see PowerPoint), the surface water area has, due to large over-abstraction for irrigation, shrunk by some 75% between 1960 and 1995. Small, crescent-shaped lakes called oxbow lakes can form in river valleys as a result of meandering. The slow-moving river forms a sinuous shape as the outer side of bends are eroded away more rapidly than the inner side. Eventually a horseshoe bend is formed and the river cuts through the narrow neck. This new passage then forms the main passage for the river and the ends of the bend become silted up, thus forming a bow-shaped lake. Crater lakes are formed in volcanic craters and calderas which fill up with precipitation more rapidly than they empty via evaporation. Sometimes the latter are called caldera lakes, although often no distinction is made. Most lakes are geologically young and shrinking since the natural results of erosion will tend to wear away the sides and fill the basin. Exceptions are those such as Lake Baikal and Lake Tanganyika that lie along continental rift zones and are created by the crust's subsidence as two plates are pulled apart. These lakes are the oldest and deepest in the world. Lake Baikal, which is 25-30 million years old, is deepening at a faster rate than it is being filled by erosion and may be destined over millions of years to become attached to the global ocean. The Red Sea, for example, is thought to have originated as a rift valley lake. 3.1.2. General Characteristics Lakes, as lentic (non-flowing) environments, have numerous features in addition to lake type, such as drainage basin (also known as catchment area), inflow and outflow, dissolved oxygen, nutrients and pollutants levels, pH, and sedimentation. Changes in the level of a lake are controlled by the difference between the input and output


compared to the total volume of the lake. We discussed the water balance of lakes before, in Course 1.3. Lakes can be also categorized on the basis of their richness in nutrients, which typically affects plant growth (as we saw in the unit 2.3. and 2.6.). Nutrient-poor lakes are said to be oligotrophic and are generally clear, having a low concentration of plant life. Mesotrophic lakes have good clarity and an average level of nutrients. Eutrophic lakes are enriched with nutrients, resulting in plant growth and algal blooms. Hypertrophic lakes are bodies of water that have been excessively enriched with nutrients. These lakes typically have poor clarity and are subject to devastating algal blooms. Lakes typically reach this condition due to human activities, such as heavy use of fertilizers in the lake catchment area. Such lakes are of little use to humans and have a poor ecosystem due to decreased dissolved oxygen. Further, we can divide lakes into three zones: the littoral zone, a sloped area close to land; the photic or open-water zone, where sunlight is abundant; and the deep-water profundal or benthic zone, where little sunlight can reach. The light depth or transparency is measured by using a Secchi disk, an about 20-centimeter (8 in) disk with alternating white and black quadrants. The depth at which the disk is no longer visible is the Secchi depth, a measure for transparency. The Secchi disk is commonly used to test for eutrophication. 3.2. Monitoring (see also Chapman 7.5) Lakes and reservoirs can be subject to several influences that cause water quality to vary from place to place and from time to time. Conducting preliminary surveys is therefore a prerequisite for successful monitoring. Assessment of bathymetry (depth contours) is required, as well as research on (in)homogeneity, overall sediment mapping (e.g. grain size distribution), etc. In general, it can be stated that the number of stations needed for lake monitoring strongly depends on the (in)homogeneity of the lake. For a vertically as well as horizontally mixed lake, one station, anywhere, will be sufficient. The criterion for "well-mixed" will mainly be based on statistical evaluation (see Course 4). Also here, often large cost reductions can be achieved by optimising the monitoring. In general, more stations will be needed for:

• Large and/or irregularly shaped lakes, again using above criterion, which can then be expanded as follows: "one station per homogeneous area"

• Large variations in water depth and sediment composition (the latter affecting water quality).

Finally (or in fact, as the first criterion to be asked; see Course 3.1.), the monitoring objectives must be taken into account (see PowerPoint), e.g.:

• Ambient monitoring of overall water quality • Input/output budgets • A "one-time" intensive research on the impact of, for example, an industry.

There are various factors that can cause inhomogenities in the water quality of lakes and reservoirs:


- In case of eutrophication, it can be expected that the oxygen contents will be

high (often > 150% saturation) during the day-time primary production of the algae; minimum DO contents may be expected just before sunrise; similar diurnal trends can be expected for the pH values. In case of year-trend analysis, it is therefore recommended, for a station, to always sample at about the same time of day (and to note down, as always, the time of sampling).

- Vertical variations can often be connected to the occurrence of thermal

stratification found in many deeper lakes in the summer season. Due to the closing off from the atmosphere, anaerobic conditions may evolve in the lower layer, the hypolimnion. This is coinciding with clearly enhanced nutrient (P, N, Si, etc.) levels. In these stratified lakes, the monitoring scheme should in any case include samples of the epilimnion, hypolimnion (preferably just above the bottom) and 1 m above and/or below the thermocline.

Reservoirs are often characterised by different zones, each with different water qualities. Thus, the riverine zone has usually higher sediment and nutrient loadings, leading to more eutrophic conditions, than the lacustrine (lake) zone.


For water quality monitoring purposes, sampling stations should be positioned in each of the zones. Special attention must be given to extraction sites for potable water supply, which are usually on the lacustrine side of the reservoir. In DeGray lake, USA the original water quality monitoring scheme included 15 transects. By statistical evaluation of the differences between stations, the number of stations could be reduced to only five (see Fig. 7). Fig. 7A. DeGray lake, USA, with the original 15 sampling stations. Fig. 7.B. Chlorophyll a concentrations in each transect; the arrows indicate the five sites, after optimization, that represent the overall water quality of the reservoir (From Chapman, 1996.) Action List for Unit 3 • Look and listen to the PowerPoint presentation available under “Lecture”. • Read chapter 7 (7.1 and 7.2) in Chapman (1996) Further Reading Book of Bartram and Balance (1996); see Course 3.2.


Unit 4 – Water Quality variables 4.1. Physico-chemical variables There are different media which can be used for aquatic monitoring, viz. water, particulate matter and living organisms. The quality of water and particulate matter is determined by physical and chemical analysis, whereas living organisms can be used for so-called biological water quality monitoring (see 4.2.). The choice of the water quality variables will depend on the objectives of the programme, the occurrence of the variables (it has no use to produce, year-after-year, lists with “non- detectables”), the potential impacts (toxicity) and financial resources. Water used for irrigation will require quite different monitoring variables than water used for recreational purposes or drinking water extraction. A short overview will be presented here of the different water quality variables: • Temperature: a basic parameter, important for all chemical and biological

processes. Large fluctuations are to be expected in deep lakes and reservoirs. The temperature should always be measured in situ.

• Colour: is influenced by natural (e.g. humic acids) and anthropogenic sources; it may be important in view of the aesthetic quality of the water. E.g., iron (Fe3+), though not harmful, will give a red colour to the (drinking) water and will then, though hardly toxic, not be consumed.

• Odour: is often caused by decomposition of organic compounds yielding organic acids, sulphides, etc. Odour is often an indication for bad water quality conditions (reduced O2), when H2S will be formed (smell of "rotten eggs").

• Total suspended solids (TSS): may especially be increased in rivers ("turbidity”) during storm floods; TSS may carry the large bulk of micropollutants.

• Electrical Conductivity (EC): this easily determinable parameter presents a good measure for the total ions present in the water; in many cases there is a good correlation with the NaCl concentration.

• pH: just as temperature a basic water quality parameter, of importance to virtually all biological and chemical processes; it should be measured in situ. In most natural waters, pH values will be between 6 and 8. As mentioned before, high pH (>9-10) may be found in eutrophic lakes and reservoirs during day-time.

• Dissolved oxygen (DO): is an essential component for all aquatic life cycles; concentrations < 2 mg O2/L will lead to deaths of most fish species. The theoretical maximum levels, i.e. solubility (ca. 10 mg O2/L) will largely be exceeded during day-time in eutrophic lakes and reservoirs. At higher temperatures the O2 solubility will show a clear decrease (see PowerPoint Course 3.6.). DO is mostly measured in situ, with a DO probe, but there is also a laboratory procedure ("Winkler titration").

• Degradable organic matter: high concentrations are due to wastewater discharges. As mentioned before, the term can be expressed as COD or BOD: Chemical and Biochemical Oxygen Demand, and is thus related to the dissolved oxygen levels.

• Ammonium: high levels (> ca. 2 mg NH4+-N/L) usually indicate pollution by

wastewaters; ammonia exerts a relatively high “oxygen demand” in the conversion to nitrate. At high pH (> 9.5), ammonium is mainly in the (toxic) NH3 - form.

• Nitrate and nitrite: high levels of NO3- may be due to fertilizer run-off and/or to

nitrification. Nitrate can be the “limiting nutrient” for algal growth, especially in


saline and brackish waters. Nitrite (NO2-) is an intermediate in both the NH4

+ → NO3

- (nitrification) and NO3- → N2 (denitrification) reactions. NO2

- levels are usually < 0.1 mg/L; relatively high values often indicate inefficient conversions.

• Phosphorus compounds: inorganic dissolved phosphate (ortho-phosphate) is usually the limiting nutrient for algal growth in fresh waters, leading to minimum (near-zero) values in the summer in lakes and reservoirs; the “total phosphorus” concentration is much more constant during the year. Ortho-phosphate is, at normal pH, dominantly present in the (quite soluble) HPO4

2- and H2PO4- forms,

rather than as (insoluble) PO43- .

• Major ions (Ca2+, Mg2+, Na+, K+, Cl- , SO42-, HCO3

-, etc.): these are mainly due to geological, climatic and geographical conditions, and are less coming from anthropogenic sources. In this respect, these parameters can be monitored less intensively than the before mentioned ones, also because of their less adverse (or even beneficial) effects. For irrigation purposes, high Na+ values are unfavourable for the soil structure (decreased permeability); therefore a low SAR (sodium adsorption ratio) is preferable: SAR=[Na+]/(√([Ca2+]+ [Mg2+])/2) ,expressed in milli-equivalents/L; see PowerPoint Unit 3.6.4.

• Alkalinity and acidity: representing the pH buffering capacity of a water sample with respect to acids and hydroxides addition, respectively. The terms are dominantly brought about by the CO2/(bi)carbonate/CaCO3 (limestone) system in nature.

• Other inorganic variables such as sulphides, silica, fluoride and boron should be monitored in case of serious problems (e.g. high F- contents in groundwater, from mineral rocks). The same holds for arsenic, a major problem in many groundwaters (e.g. in Bangladesh).

• Microbiological indicators such as E coli and faecal coliforms can be associated with micro-organisms that cause diseases. Most of these originate from domestic wastewater discharges.

• Eutrophication status/algae primary productivity, often expressed as the chlorophyll-a (chl-a) concentration. Values can vary from < 3 µg/l to > 100 µg/l depending on the trophic state of a water body.

• Heavy metals (Pb, Cd, Zn, Hg, Cu, etc.): usually these components are not part of basic monitoring programmes, because of the complexity of analysis in the often low concentration ranges encountered in practice. The dominant fraction is found in the particulate phase; therefore determination in lake sediments often yields interesting results, e.g. on the history of the pollution sources (see Course 2.4.).

• Organic micropollutants such as PCBs (poly-chloro-biphenyls), PAHs (polycyclic aromatic hydrocarbons), and pesticides (DDT, aldrin, dieldrin, atrazine, etc.) can only reliably be measured in advanced monitoring programmes. These micropollutants, together with the heavy metals, have a strong tendency for bioaccumulation in the food chain.

• Hydrological parameters (flow, discharge) are part of routine river monitoring programmes. Flows (m/s) can be measured with calibrated propellers or, more advanced, using ADCP (Acoustic Doppler Current Profiler). River discharges (m3/s) can then be evaluated from the "wetted area" (m2) of the river bed.

For most purposes, 15-30 parameters will be sufficient to adequately describe the basic water quality. The list of variables for the basic WHO-GEMS monitoring programme (see Table 1) contains some 20 standard variables. Nowadays, a more


comprehensive list of parameters in the GEMS programme will additionally include (see http://www.gemstat.org ):

• SAR • BOD and/or COD • Total and organic nitrogen • Microbiology: Giarda and Cryptospiridium spp. • (Heavy) metals; arsenic • Organic micropollutants such as organo-chloro pesticides and PCBs .

Table 1.Variables used in GEMS/WATER programmes for basic monitoring (from: Chapman, 1996) In case of very limited resources, a minimum list of parameters could be: - Hydrology, for rivers - Total suspended solids/turbidity - Temperature and pH - Electrical conductivity - Dissolved oxygen - Nitrate, ammonia and ortho-phosphate; periodically: total P and N. More complex, expensive programmes may analyse >100 variables. In the Netherlands, the complete list of variables has, over the last decades, increased to


some 250 parameters, most of them as micropollutants (see Fig. 8.). To avoid a strong increase in the monitoring cost, much optimization has been reached with respect to the monitoring frequencies and, especially, the number of stations.

Fig. 8. Increase in the number of monitoring parameters between 1952 and 2002 in the fresh "governmental waters” of the Netherlands. (From: unpublished Report Dutch Ministry of Infrastructure and the Environment). (↓ = optimization programmes)

4.2. Biological Water Quality Monitoring

4.2.1. Introduction Water quality can be described in terms of physical, chemical and biological characteristics. Changes in the water quality can produce diverse biological effects in the aquatic ecosystem, ranging from a complete disappearance of fish life, to subtle changes in the behaviour of water flees. Changes like these indicate that the ecosystem and its associated organisms are under some stress, e.g. caused by a spillage of pollutants into the water stream. Since the biological community has a much longer “memory” (viz. at least the life time of the organisms) than the physico-chemical water environment, biological methods can be extremely useful in the assessment of water quality. A number of techniques can be differentiated in biological water quality monitoring: • Biomonitoring, to characterize the quality of ecosystems. The most widely applied

biological method used in this respect is the monitoring of indicator bacteria (e.g. E coli spp.) for faecal pollution. Toxicity tests can be performed with a wide range

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of chemicals and organisms, under many different conditions in water and sediment systems. For the monitoring of lake eutrophication, the occurrence of certain algae species is a good indicator. Another common technique is the monitoring of presence or absence of different species families, of macro-invertebrates (4.2.2.).

• Bioaccumulation monitoring, making use of the accumulation of especially heavy

metals and organic micropollutants in fish, mussels, etc. (see 4.2.3.). • Early warning biomonitoring, in which the behavioural changes of e.g. fish under

sudden water quality changes, is monitored (see 4.2.4.). When designing a monitoring programme, biological methods should be considered along with physico-chemical approaches for a proper interpretation of results. Financial savings can sometimes be made by using biological methods to “trigger’ the need for intensive and sensitive chemical analyses. A disadvantage of biological methods is that it can be difficult to relate observed effects to the “environmental disturbance”; the response of organisms may also be influenced by their life stage or reproductive condition. Biological monitoring methods can therefore best be developed and interpreted by experienced biologists, though e.g. the BMWP method (see hereafter) can be carried out by any non-specialist .

4.2.2. Biological monitoring with macro-invertebrates Benthic macro-invertebrates, such as mayflies, shrimps and maggots, have widely been used in biological water quality monitoring. They have a fixed position in the stream bed, which makes them susceptible to the passing water for 24 hours per day. In this way they can serve as good “integrating monitors” during their whole life cycle (a few weeks to less than a year). Additionally, the organisms are relatively easy to sample with nets, and (if not on species level) to be identified. The benthic macro-invertebrates are especially good indicators for organic pollution in rivers and streams, with the related effects on the dissolved oxygen levels; the relative tolerance of some key groups to organic pollution is presented in Fig. 9. The quantitative assessment (counting) of the presence of the different taxonomic families, or even species, leads to “biological scores”, e.g. in the “saprobic index”, the “Trent” and “Chandler Biotic Indices”, or in the “Biological Monitoring Working Party” (BMWP) (see e.g. http://www.cies.staffs.ac.uk/origbmwp.htm). As mentioned before, the above method is relatively simple and cheap, and it offers good integrative results. The measurements should regularly be repeated, say, in a frequency of 1-2 times per year to detect long term trends in the water quality. Disadvantages of the method are: - The biological communities also depend on the substrate present (sand,

boulders, clay, etc.). - Comparison between different regions (climates, altitudes) is may be difficult;

this holds even for the upstream/downstream regions of rivers.


Fig. 9. Relative tolerance to organic pollution of some key groups of aquatic macro-invertebrates.

4.2.3. Bioaccumulation monitoring Many organisms have been found to accumulate certain contaminants in their body, especially into the fatty tissues (bioaccumulation). Contaminants can be ingested together with the normal food, or may be passively adsorbed through the body surface. When an organism which has accumulated a contaminant is eaten by another organism, the latter again accumulates the contaminant to a, perhaps, lethal level. This increase in concentration in the sequential stages of the food chain is known as biomagnification (see Course 2.4.). This can be a way of detecting measurable concentrations of micropollutants, without having to rely on sophisticated instruments, as would have been necessary in case of analysis of the original water sample. An application of this is the “World Mussel Watch Programme”, comparing micropollutants’ levels in mussels world-wide. The mussels are placed in nets, lowered into the water and left for some time there. After that, the increase in the micropollutants' levels can easily be assessed. 4.2.4. Early warning biomonitoring Biological early warning systems rely on an immediate biological response in the test organisms placed in the water system under consideration. The further action usually


takes the form of a more detailed investigation of the causes, including chemical monitoring. If these systems are used nearby important water intakes, the water inlet may temporarily have to be closed down. In practice, the position of the sampling sites will be set by the “response time” required for sampling, analysis and interpretation. Common organisms used in early warning biomonitoring are fish like goldfish; see Fig. 10a.Normally, the fish will move upstream; however in case of some “stress”, like a pollutant, the fish will move away with the stream, touching a sensor. When an (often automated) recording system has registered a certain exceedance level, an alarm will warn the supervisors, who can then take appropriate measures. Although the system is quite susceptible to “false alarms”, it is still often used at water extraction points of drinking water companies. Another early warning biomonitoring system makes use of the specific swimming activities, and changes herein in case of stress, of Daphnia spp, the water flea; see PowerPoint). A third example is the behaviour of mussels, Dreissena spp. When a toxicant enters the water, the mussels will close their valves. This can again be registered by a computer, which will activate an alarm in case of exceedance of some “normal behaviour level”; see Fig. 10b. Fig. 10.a A dynamic fish test for continuous monitoring of toxicity in water. (From: Chapman 1996); Fig. 10.b An example of a “mussel monitor”

a

b


4.3. Water Quality Monitoring in the European Union Water Framework Directive

Fig. 11.Member states of the European Union (2014) The European Union consists of 28 Member countries (2014). In the EU Water Framework Directive (EU-WFD), established in 2000, aim is to reach good water quality statuses for all surface and ground waters by the year 2015. For this, often international River Basins must be founded (see e.g.: http://ec.europa.eu/environment/water/index_en.htm). Detailed information on the EU-WFD has been uploaded on the platform. With respect to surface water quality monitoring, an overall pragmatic approach is chosen, in which, because of the diversity in e.g. socio-economic circumstances within the EU, Member states may apply the monitoring principles in a flexible way, as long as deviations are “defendable”, “transparent” and of limited time–frame. Up to a certain level, the monitoring is thus “tailor-made”. In the EU-WFD, monitoring of the following categories of parameters takes place (see the Course Unit PowerPoint for the detailed list of variables, in rivers and lakes monitoring) :

• “Chemical” monitoring: o Temperature, pH, alkalinity, conductivity, etc. o DO, temperature; o Nutrients o Priority substances: heavy metals and organic micropollutants. At the

moment, the list consists of >150 parameters. However monitoring is only necessary for those substances which can be expected to occur.

• “Ecological monitoring”: o Plankton, fish, macro-invertebrates, etc.


o Hydromorphology, e.g. hydrology, "continuity" (presence of dams as barriers for fish migration; of shallow/deep parts in rivers).

For the overall assessment of water quality, both the Chemical ("one out, all out!") and Ecological Status should be “good”; see Fig. 12.

Bad status Good status

Bad status

Poor status

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(differs moderately from type specific

conditions)

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(slight changes from type spec.

conditions)

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(close to undisturbed conditions)

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Ecological statusEcological statustargetstatus

max. ecol.potential

reference

bioticelementsabiotic

elements

Water-quality status = Chemical status + Ecological status

YardstickYardstick

OVERALL ASSESSMENT

Fig. 12. Overall water quality assessment in the EU-WFD. Both for the chemical and ecological status, minimally the “target status” should be reached. 4.4. Recent developments in water quality monitoring Over the last decades, there have been new methods and techniques such as (see PowerPoint):

• Ferry Boxes; • GIS, remote sensing, the latter for e.g. eutrophication (chl-a) and turbidity • Sensors, often automated, for pH, salinity, nutrients, etc. • Smart phones.

Action List for Unit 4 • Look and listen to the three PowerPoint presentations available under “Lectures",

including Unit 4.2.: "Biological Monitoring" and 4.3.: "Recent developments". For the latter, there is also "additional reading".


Unit 5 – Monitoring Frequencies and Optimizations 5.1. Monitoring frequencies The monitoring frequency at stations where water quality varies considerably should be higher than at stations where the quality remains relatively constant. Statistics show us that the reliability of our conclusions increases with the square root of the number of observations; see also Course 4 on “Data handling and presentation”. The required monitoring frequency will also be dependent on the objectives of the monitoring programme. - In trend analysis, monthly intervals will generally suffice. - Early warning monitoring may need a daily or even hourly frequency to ensure

sufficient time for taking appropriate measures in case of calamities. Finally the frequency will depend on the available human and financial resources. The monitoring frequency for the GEMS/WATER stations varies between 1-2 x per month, for rivers, once per month, or lower, for lakes, to once per year for large, stable ground water aquifers (see Table 2.).The low frequency for baseline stations: streams and headwater lakes, is due to the monitoring objectives for these stations: "trend monitoring over the years". Further, it can be seen that (maybe in contrast to expectations), the monitoring frequency for rivers in higher in smaller river basins.

Table 2. Monitoring frequency for GEMS/WATER stations


As mentioned before, individual samples at a given station should, as much as possible, be obtained at the same time of the day because of diurnal variations in water quality (dissolved oxygen, pH). Exceptional conditions of stream flow are frequently of interest, because it is at maximum and minimum flow rates that extreme values of water quality are reached. An illustration of this can be observed in Fig. 13 in the monthly frequency

Fig. 13. Daily discharges during 1987 at Ecublens-les-Bois on the Venoge river. Monthly sampling intervals and the periods sampled for storm events are also indicated (from Chapman, 1996). of sampling in the Venoge river (Switzerland). We see that in the normal monthly sampling routine, many storm events (assessed by daily discharge measurements in the river) have been missed. This problem could partly be solved, using the same financial resources, by synchronising the water quality measurements with the discharge regime, e.g. by using automated samplers. Above problems with short-duration storm events are especially present for small river basins, say < 1000 km2. For large river basins (>100,000 km2) these events are much more “smoothened out”; here, monthly intervals sampling will generally yield reliable, representative results, cf. Fig. 14. Fig. 14. Optimum ranges of sampling frequencies for riverine fluxes of total suspended solids and major ions as a function of river basin areas (Chapman, 1996)


5.2. Some aspects of optimization Optimization of monitoring programmes is an indispensable tool for acquiring best possible results, for least cost; statistical tests are commonly used here; see Course 4. These programmes can entail, amongst others, a reduction in the number of monitoring stations and/or frequency or a reduction in the number of parameters. An important concept is the "allowable error" or "detectable trend", indicating the level of accuracy that is necessary to still be able to come to meaningful conclusions (e.g. whether or not this year's phosphate levels in a lake have decreased significantly compared to last year's data). Fig. 15 illustrates the sharply decreased number of monitoring stations in the Dutch "governmental fresh waters", between 1978 and 1996. The cost savings were used for being able to cope with the ever expanding list of monitoring parameters (see Fig. 8).

Fig. 15. Overview of the monitoring stations in the Dutch governmental fresh waters between 1972 and 1996. (From: unpublished Report Dutch Ministry of Infrastructure and the Environment)


Monitoring frequencies in the EU-WFD The minimum monitoring frequencies for the various categories are presented in Table 3. Frequencies are often higher, e.g. in the Netherlands: 1x per month for physico-chemical variables.

Table 3. Minimum monitoring frequencies for the EU-WFD surface water Action List for Unit 5 • Look and listen to the PowerPoint presentation available under “Lecture”.

Unit 6 – Field and laboratory work 6.1. Fieldwork 6.1.1. Sampling, preservation and field measurements( cf. Fig. 16-18) The fieldwork associated with the collection and transport of samples will account for a substantial proportion of the total cost of a monitoring programme. Therefore, the sampling expeditions should always be planned carefully and carried out in such a way that efforts are not wasted. This holds e.g. for checking the necessary equipment and chemicals. It is good practice to follow a checklist of all necessary items and activities (see Table 3). Clear sampling protocols must have been set up beforehand.

Quality Element Rivers Lakes Transitional Coastal l

BiologicalPhyto-Plankton 6 months 6 months 6 months 6 months

Other aquatic flora 3 years 3 years 3 3

Macro invertebrates 3 years 3 years 3 years 3 years

Fish 3 years 3 years 3 years

Hydromorphological

Continuity 6 years

Hydrology continuous 1 month

Morphology 6 years 6 years 6 years 6 years

Physico-Chemical Thermal Conditions 3 months 3 months 3 months 3 months

Oxygenation 3 months 3 months 3 months 3 months

Salinity 3 months 3 months 3 monthsNutrient Status 3 months 3 months 3 months 3 months

Acidification Status 3 months 3 months

Other Pollutants 3 months 3 months 3 months 3 months

Priority Substances 1 month 1 month 1 month 1 month


Table 3. Checklist for preparing fieldwork. (From: Bartram and Balance, 1996)

Personnel that carries out the fieldwork must be fully trained in both sampling techniques and field test procedures, and must have a good idea of the monitoring objectives in order to react in a sound way in case of problems, such as inaccessibility of a regular site.


The water samples should be collected in clean, pre-rinsed glass or polythene bottles, and must then can then be stored in a way that is dependent on the chemical constituents to be analyzed (see Table 4). For lake monitoring a suitable depth water sampler can be used in case of stratified conditions. Other typical lake monitoring techniques include:

• Secchi disc readings, for a crude estimation of light penetration and eutrophication

• Sediment traps (which should have a cylindrical shape (in contrast to Fig. 16)), for monitoring sedimentation and resuspension rates

• Sediment grab samples and vertical sediment core samples. The sample bottles should always be clearly labelled with all relevant information (site, water depth, date, time, etc.). All relevant information (date, time, worker’s name, river flows, weather conditions,..) should also be noted in a special worksheet or notebook (see Fig. 18).

Fig. 16. Sampling procedure in a river, and lake monitoring techniques. (From:Bartram and Balance, 1996) The type of samples taken could either be: • Grab samples, taken from selected location, depth and time , or • Depth integrated; • Time integrated (often automated samplers are used in this case). • Discharge integrated, e.g. for industrial effluents.


Fig. 17. top left: Secchi disc; top right: field instruments DO, pH, EC, temperature; below: field kit analysis

After sampling, a filtration may be necessary in order to differentiate between the “dissolved” (over 0.45 µm filter) and the “particulate” phases of the chemical variables. Some determinants should be analyzed directly in the field (electrodes for EC, pH, O2, temperature). It is recommended not to carry out these measurements in the sample bottle itself (could cause contamination!). Many other constituents may be analyzed in the field as well, with the help of field kits. The reliability of these is usually somewhat less than for laboratory equipment, though marked quality improvements have been reached over the last few years. Finally, for the determinants to be analyzed in the laboratory, preservation protocols with respect to cooling or addition of preservatives should carefully be adhered to (see Table 4). In all cases changes in the sample composition must be avoided or minimized.


Fig. 18. Example page from a field notebook. (From: Bartram and Balance, 1996)


Determinant Material of sample container: Polythene; glass; borosilicate glass

Method of preservation Maximum storage time

Ca, Mg, Na, K P, acid washed HNO3, pH 1-2 1 month

Anions (Br, F, Cl, NO3, PO4, SO4)

P or G 1-5ºC or freeze -20ºC Up to 1 month. Filter on-site

Alkalinity, HCO3 P or G Cool to 1- 5ºC 24 hours

BOD P or G 1- 5ºC or freeze to -20ºC 24 h.; 1 month, respectively

COD P or G H2SO4, pH 1-2 1 month

Nitrogen, ammonia P or G H2SO4, pH 1-2 and cooling 1-5ºC

21 days. Filter on-site

Nitrogen, nitrate P or G HCl, pH 1-2 or cool to 1-5ºC or freeze –20ºC

1 day - 1 month

Nitrogen, nitrite P or G HCl, pH 1-2 or cool to 1-5ºC or freeze –20ºC

1 day – 1 month

N, Kjeldahl and TN P H2SO4, pH 1-2 or freeze to -20ºC

6 months in dark, TN: 1 month

Phosphorus, total P/G/BG acid washed 1 H2SO4, pH 1-2 or freeze to -20ºC

6 months

Phosphorus, dissolved P/G/BG acid washed Cool to 1- 5ºC or freeze to -20ºC

1 month. Filter on-site

Chlorophyll-a P or G (brown) 1-5 0C or freeze to -20ºC 1 day, 1 month, respectively

Heavy metals, except Hg P/BG acid washed HNO3, pH 1-2 6 months

Mercury BG acid washed HNO3, pH 1-2, add K2Cr2O7 (0.05%)

1 month

Mineral oil G pH 1-2 with HCl or H2SO4

1 month

Organo-chlorine pesticides G 1-5 0C 1 day-1 week

Table 4. Recommended preservative treatments and maximum permissible storage times for selected water quality variables, according to ISO 5667-3 (2008). (From: http://www.2dix.com/pdf-2011/iso-5667-3-pdf.php)

1 Both for dissolved and total P: detergents often contain phosphates, so should not be used for cleaning !


Overview: Handling and Preservation of Water Samples See also PowerPoints of Fred Kruis and of Centre of Water Management, the Netherlands Waters are susceptible to change as a result of physical, chemical or biological reactions which may take place between the time of sampling and the analysis. If precautions are not taken, at the time of sampling, changes may occur rendering analytical data unrepresentative. Changes may occur due to:

• consumption of certain constituents by bacteria, algae etc.; • certain compounds being oxidised by the dissolved oxygen in the sample; • precipitation from the liquid, e.g. calcium carbonate, aluminium hydroxide; • loss into the vapour phase; • absorption of carbon dioxide from the air, changing the pH value; • adsorption of metals and certain organic compounds onto the container's surface; • depolymerisation of polymerised products and vice versa.

These changes will be affected by the storage temperature, exposure to light, the nature of the container used and the time between sampling and analysis. In adverse conditions, changes can occur in just a few hours. Fortunately, preservatives are available to prevent these changes. However, it must be borne in mind that methods of preservation are less effective with heavily contaminated samples than with those with light contamination. See also discussion on "representative" and "valid" samples, in the PowerPoint of Fred Kruis. General Considerations (see also previous text, Table and figures): • In most cases, fill the sample containers to the brim and stopper them so that no air is left

above the sample. • Use an appropriate container. For example, polyethylene bottles should not be used for

hydrocarbons, since adsorption on to the bottle's surface is likely to occur. • Glass containers are suitable for most determinations. Brown bottles should be used in case

photosensitive reactions are likely to occur. • Containers must be clean. Whilst this may seem obvious, scrupulous cleanliness is important

due to the low detection levels now being adopted. For P determination, care must be taken not to use detergents containing phosphates !!

• Samples should be kept at a temperature below that at the time of filling. Cooling between 2 degrees and 5 degrees (i.e. in melting ice, refrigerator or cool bag with ice packs) is adequate, but not suitable for long-term storage.

• Suspended matter, sediment, algae and other micro-organisms should be removed at the time of sampling by filtration or centrifuging or immediately on receipt at the laboratory. Filtration should not be carried out if the filter is likely to retain one or more of the constituents to be analysed.

• Generally filtration is achieved by use of 0.45 micron filter paper.


2v + v = v 0.80.2

6.1.2. Hydrology Knowledge on the water flow and discharge of rivers is essential in water quality monitoring. Discharges have a direct influence on water quality, since “Dilution is not the solution to pollution”, but it helps.... In the following, we will follow International Standards ISO 748-1979(E). In order to accurately determine stream flow, measurements must be made of its width, depth, and speed (velocity) of the water at a representative number of horizontal and vertical points across the stream. To develop a stream-stage/stream flow relation (rating curve), the stream flow must be measured at a number of different stages. A propeller is a common apparatus for doing that (Fig. 19). Stream velocity (m/s) will be different for both the transect (width) of the river as well as its depth; cf. Fig. 19, so velocities will have to be measured in a number of segments. In practice, a river width of 10 m is, for example, divided into 5 segments; at each of the 5 points, the "average" water velocity is determined at 2, 3,.. water depths, to come to a depth-averaged velocity (m/s). Together with the width of segment (in above case: 2 m), and its depth (=water depth at the segment), we arrive at the discharge (m3/s). Fig. 19. Propeller for river flow measurements; schemes for discharge determinations

A more simple method is using a floating object like an orange. Estimating its velocity (m/s), e.g. 10 times over a distinct river stretch, and computation of the cross-sectional area (depth x width, m2) will lead to an estimation of river discharge, m3/s. A correction factor, usually 0.8 or 0.9 x may be necessary to account for the lower stream velocities deeper into the river.


6.2 Physico-chemical analyses

6.2.1. Methods and cost In the use of the analytical techniques in the field and laboratory, well validated, robust standard methods must be used, e.g. according to the book of "Standard Methods" APHA/AWWA/WEF (2012). It is useful to make an operational differentiation into: - “Conventional”, cheap methods:

- Titrations for e.g. chloride, alkalinity, hardness, chlorine. - Spectrophotometric determinations (for phosphate, ammonia, nitrate, iron, etc.)

- Selective electrodes (pH, oxygen, fluoride, redox potential, etc.). - “Advanced”, expensive methods such as: - Atomic absorption spectrophotometry (AAS) for (heavy) metals - Gas chromatography (GC) for pesticides, PAHs, etc. - HPLC (High-performance liquid chromatography) for e.g. amino acids and sugars. The latter category has some 10-20 more investment cost than the conventional techniques. Besides, these instrumentations need much operational manpower, expertise and maintenance, good facilities as well as strict quality control. If possible, combined facilities within one geographical region (capital, district) should be used here; in many countries, monitoring laboratories are indeed organized in lower level regional laboratories, for basic determinations, and more advanced, higher level central laboratories. As an example, below list presents representative commercial prices (2009), in a well-equipped Certified laboratory in Indonesia, all in US dollars: • BOD; COD: $10 per analysis • Nutrients: - PO 4-P, NO3-N, NH4-N: $5 per analysis - Ptot., Ntot. : $10 per analysis • Chl-a: $15 per analysis • E-coli (MPN): $10 per analysis • Heavy metals (AAS): $35 per analysis in water; $75 in sediment and biota. Per analysis, all main heavy metals except Hg are analyzed together. • Pesticides (GC-MS): $50 per analysis (of a group of pesticides) in water; $100 in sediment and biota • Cost for Biological Water Quality Assessment: $ 50 per station (labour cost only). Table 5 gives an overview of analytical "cost" for water quality variables, expressed as investment cost, labour time and operational costs. The data comes from 1996 and present investment cost may be quite different (not necessarily more expensive!).


Table 5. Analytical cost for water quality parameters (1 ECU ≈ 1 US)

6.2.2. Analytical quality assurance and control (QA/QC) Quality control will be necessary in all stages of the monitoring cycle such as in (re)defining objectives, stations and monitoring frequencies. A special item is quality assurance and control (QA/QC) in the laboratory. In certified, top-quality laboratories in the world, the allocated resources for QA/QC will be some 20% of the total budget. QA/QC in the laboratory involves: • Well-trained, critical personnel, working in adequate facilities (instrumentation,

cooling, space, storage facilities, etc.) and under optimum working conditions; the management structure of the laboratory should be defined clearly.

• The daily running of Standard Operating Procedures (SOP) for the whole routine of sample handling (receipt, storage, analysis, disposal), and the use of well-validated, robust standard procedures of analysis.

• Accurate and controlled reporting of the data. • A frequent control of methods, instruments (calibration !) and personnel.


The laboratory staff should be involved in the preparatory steps before the analysis: sampling, storage and transport. They must also be familiar with the objectives and the general set-up of the monitoring programme. Day-to-day practices for assuring high quality data involve: using clean glassware and chemicals; careful, scrupulous adherence to the prescribed methods, and tidiness on the work floor. This can be summarised with the term: Good Laboratory Practices (GLP). Specialised Quality Control and Assurance in the laboratory may be carried out via a number of techniques, which generally involve some statistical tests for the reliability of the laboratory results. See PowerPoint Course ..

• Accuracy (estimated average close to actual one), vs. precision (repeatability); • Rounding off correctly; how to deal with "outliers"

QA/QC methods could either be: Internal control, usually carried out on a daily basis, by e.g.: • Use of blanks, duplicates and of “spiked” samples; these samples should be

unrecognizable for the analysts to avoid extra-careful working; • Checking the ionic balance, and use of other “tricks” (e.g. PO4-P < Ptot.; dissolved

heavy metals < total heavy metals); • Shewhart Control Charts: see Annex and PowerPoint. In any case, samples should for some time be stored in a refrigerator to enable possible re-analysis. External control, which may be carried out 1-2 times per year: • Samples of “Certified Reference Material" (CRM) of known composition can be

used to critically check the whole analysis cycle in the laboratory; • Inter-laboratory checks (“Ring" or "Round Robin” tests), such as carried out in the

GEMS-WATER monitoring programme. Ring analyses give insight in the general errors made in the group of laboratories as well as in the performance of the individual laboratories.

The laboratory supervisor should always be aware of the tendency of analysts to simplify procedures; this may lead to completely erroneous results. Also, the supervisor should create an open atmosphere, where it is possible to make mistakes and discuss them. Finally, it must be realized that 100% perfect results can never be reached. The quality goals will always be a compromise between the quality needed and the available resources. Table 6 presents a list of seven monitoring data, and describes errors in the various results. Use is made of, amongst others, the ionic balance, in which the concentration sum of the major cations must be equal (5-10% error allowed) to that of the anions; concentrations are expressed in μequivalents/L: μ-eq/L = |μmole/L x charge|. Typical errors indicated in Table 6 are:

• Incorrect ionic balance • Incorrect rounding off, e.g. pH = 7.72. Final analysis results can never have

more significant figures (s.f.) (e.g. 6 s.f. in result: 8.32865 mg/L), if the values on which this result are based (like pipette and burette readings in titration) have 3-4 s.f.

• Interchanging of columns; incorrect multiplication with factor 10, 100,..

In all cases, an "Expert opinion" is needed to make decisions how to make corrections; see assignment...


Table 6. Example of a list with “questionable data” (From: Chapman, 1996)


Action List for Unit 6 • Look and listen to the PowerPoint presentations available under “Lectures Unit 6”,

including the one kindly provided by the Centre of Water Management, the Netherlands. This organisation is a part of the Ministry of Infrastructure and the Environment and is responsible for the national network of roads and for larger lakes and (international) rivers ("governmental waters")

• Read chapter 3 in Chapman et al. • Complete the assignment WQA-4 and put on the platform. • See in "additional materials" : sediment core sampling"

Assignment WQA-4: "Expert opinion"

See the platform for an EXCEL file with a 2-years data set from a wetland. All samples come from the same station and can be considered as replicates, since no seasonal trends have been detected for this wetland. Please give an expert opinion, discussing which data should be modified (and how) or should be deleted. Hint: reject as few data as possible; "errors" must be really clear !

YouTube illustrations − Water sampling, Secchi disc reading, on-site measurements:

https://www.youtube.com/watch?v=0avTfGUyHBM (part 1) https://www.youtube.com/watch?v=K4KL32KpHZ0 (part 2)

− The following movie shows sediment sampling techniques: http://www.youtube.com/watch?v=c8WDv1s5b0k

ANNEX: Shewhart Control Chart; see PowerPoint on QA/QC


Unit 7 - Water Quality Assessment and Reporting 7.1. Water Quality Assessment Water quality assessment can be defined as the evaluation of the physical, chemical and biological nature of water in relation to natural quality, human effects and intended uses (irrigation, drinking water, ecology, etc.). Water quality assessment is, together with reporting, an essential last step in the monitoring cycle. Here, conclusions are drawn with respect to “the” water quality, in relation to the water quality standards and guidelines set for different water uses. Important information on year-to- year trends in water quality can be also made in this evaluation stage. In the setting of guidelines as well as in the evaluation of water quality, use is often made of statistical parameters such as medians and 90th percentiles. Also in effluent permits statistically related standards are often given with respect to the exceedance of concentrations, e.g.: maximum levels, “never” to be exceeded, together with 90th percentiles, indicating the levels that only for 10% of the effluent samples may be exceeded. A “median concentration” is the value that is exceeded in 50% of the cases; a 90th percentile phosphate concentration of 0.5 mg/L indicates that this concentration is exceeded in only in 10% of the monitoring data. For further details on statistical assessment of water quality data, see Course 4. “Water quality indices” are commonly used for an overall interpretation of the monitoring data. For physico-chemical parameters, the water quality indices are based on lumping together different parameters. At least 30 water quality indices are currently being used over the world, with the number of variables ranging from 3 up to 72. Practically all of these include at least three of the following parameters: O2, BOD and/or COD, NH4-N, PO4-P, NO3-N, pH and TSS. Before you continue with the lecture notes, please read the paper of Helmond & Breukel (1997), available in the Additional Reading section. A frequently used index is the Prati index; see the Table below (and full paper in Additional Materials); see also explanations in the PowerPoint. Some disadvantages of water quality indices are: • They only give an overall picture of water quality, lumping together the various

parameters involved. • “Comparing apples with pears”: some of the parameters involved may be more

important than others. Weighing factors can therefore be introduced. E.g. weighing factors = 4 could be assigned to BOD and DO, vs. a factor = 1 for relatively unimportant factors such as water temperature.

• A situation may arise that the overall water quality index is up to standard, whereas the water quality with respect to one, or a few parameters, may be extremely bad. A solution could be to base the value of the overall water quality index upon the “worst case parameter."


Table 7. Components of the "full" (above) and "simplified" Prati index for water quality assessment. The below Index is based on 8 variables, and rates the water quality from class 1 (unpolluted) up to class 5 (extremely polluted). Class 1 2 3 4 5 index interval 0.1-1 1-2 2-4 4-8 10 pH 6.5-8.0 6.0-6.4 &

8.1-8.4 5.0-5.9 & 8.5-9.0

3.9-4.9 & 9.1-10.1

<3.9 & >10.1

% O2 88-112 75-87 & 113-125

50-74 & 126-150

20-49 & 151-200

<20 & >200

BOD520 (mg/L 0.0-1.5 1.5-3.0 3.0-6.0 6.0-12.0 >12.0

COD (mg/L) 0-10 10-20 20-40 40-80 >80 Suspended solids (mg/L)

0-20 20-40 40-100 100-278 >278

NH3 + NH4+ (mg/L) 0-0.1 0.1-0.3 0.3-0.9 0.9-2.7 >2.7

NO3- (ppm) 0-4 4-12 12-36 36-108 >108

Cl- (ppm) 0-50 50-150 150-300 300-620 >620


Example (simplified PRATI index): use the above transformation formulas to calculate the sub indices and then calculate the average to obtain the overall index. Parameter value Points pH = 4.5 6.0 O2 = 70% 2.5 BOD5

20 = 5 ppm 3.5 COD = 20 ppm 2.0 Susp. solids = 35 ppm 2.0 NH3 + NH4

+ = 0.8 ppm 3.5 NO3

- = 20 mg/L 2.5 Cl- = 100 ppm 1.5 Σ = 23.5 Then the Prati index = Σ/n = 23.5/8 = 2.9, so between 2 and 4 --> class 3 (moderately polluted).

7.2. REPORTING The whole system of water quality monitoring is aimed at the generation of reliable data, which must then be processed and presented in a way that is understandable, also for the non-specialist. Much too often, water quality data are buried in annual reports, with the data presented in tabular forms only, without any statistical assessment, interpretation or graphical presentation. Only with this latter processing, the actual water quality data can be compared with the objectives set, and appropriate measures, if necessary, can be taken. A clear and understandable reporting of data is therefore a last and essential step in a water quality monitoring programme. It can always be shown to be cost-effective, since it enables optimization (usually a reduction of future efforts) of the water quality monitoring programme. For the data handling and management, computer software can be used for the processing of numerical data and performing statistical tests, as well as for carrying out graphical presentations. Statistical tests comprise calculations of means, medians, standard deviation, the exclusion of “outliers”, carrying out regression and variance analysis, etc. In the (statistical) processing, much care should be taken that the integrity of the original “parent” data base is always secured. GIS (geographical information system) is specifically designed to relate monitoring data to geographical locations, in the form of maps. Data on surface and ground water quality can thus be overlain with data on population, land use or geology. Graphs can communicate complex ideas with clarity, efficiency and precision. The general objective is to concentrate a large amount of quantitative information in a small space, so that a comprehensive overview of that information is readily available to the reader. Examples of graphical presentations are: bar graphs, time series and “box and whisker plots” (see Fig. 20); see Course 4.


Fig. 20. upper graph: Bar graph with 95% confidence intervals; lower graph: Box-and-whisker plots to display time series information. (From: Chapman, 1996) Finally, the water quality monitoring report must show a clear structure, and be understandable, also for non-specialists. It must at least contain: - A short summary; - An introduction on the objectives of the programme; - A description of the region; - The different methods used, both in the field and the laboratory, including QA/QC protocols; - A clear presentation of the results followed by an analysis of these results; - Conclusions and recommendations for the decision makers. Action List for Unit 7 • Look and listen to the PowerPoint presentation available under “Lecture”. • Complete the exercise in the PowerPoint; it will further be discussed during the

Course 3. ASSIGNMENT WQA-5 Write a 2-3 page report on water quality monitoring and assessment in your country/region. Take into account (whenever possible) both the physical-chemical and biological water quality data. Focus on both monitoring and assessment. Do not refer this time to the GEMS database but try to find data from ongoing monitoring programmes of your government. Post this sign on the platform under the appropriate forum. Further Reading • Chapman (1996), Chapter 5.


Unit 8 - Groundwater pollution and monitoring 8.1. Groundwater pollution 8.1.1. Introduction Ground water is an important source for drinking water extraction. If of good quality, it needs only limited treatment before consumption to reach the quality criteria for drinking water. A strong exchange exists between surface and ground waters. This may lead to ground water pollution from surface water, or vice versa. Increasing trends of ground water pollution can be observed world-wide, due to e.g.: • Input of untreated domestic wastewater (BOD, SS, nutrients, bacteria and viruses,

etc.) • Industrial spills; mining (BOD, SS, micropollutants) • Agriculture (N03

- , pesticides, Cl- ..) , • Pit latrines and other on-site sanitation systems • Precipitation (acid rain, air-borne pollutants,..) • Waste dumps (domestic and hazardous wastes). The approach towards ground water pollution has often been : "out of sight, out of mind". However, since remediation of ground water pollution is a) difficult (it involves complicated techniques); b) slow (usually anaerobic microbial decay processes are involved), and c) expensive (it has been estimated that for the clean-up of the polluted ground water in the USA, US$ 15 billion will be needed), it follows that pollution prevention is a very important strategy. 8.1.2. The fate of pollutants in the groundwater See the PowerPoint Course 8, for general concepts in groundwater flow, e.g. porosity, permeability, and aquifer. The fate of contaminants in the groundwater is determined by transport processes as well as by physico-chemical and microbiological reactions. The advective flow of groundwater, as determined by factors such as terrain slope and soil permeability, is typically cm’s/day. However, for non-permeable clays this may be a factor 103 – 106 lower. In these latter soils, the main transport of pollutants in the groundwater works via molecular diffusion, typically in the order of cm’s/year.


Reactions that can occur in the groundwater include: - Adsorption and precipitation, which will especially take place on the “fine”

sediment material, viz. the clay particles. Above reactions will results into a retardation of many contaminants: PO4

3-, metals, organic micropollutants, etc. Pollutants like NO3

- and Cl- will however hardly slow down by these reactions. - Microbiological degradation of organic compounds; denitrification (NO3

- à N2); die-off of bacteria and viruses. Most pathogens do not survive long in groundwater: at 200C, a 90% reduction usually occurs within 10 days. However, some species may survive for more than 200 days as a result of the absence of ultraviolet light, oxygen, and because of the existing lower temperatures in the soil.

- Complexation, redox reactions and dissolution at low pH (especially for heavy

metals). Example Bacteria and virus decay proceeds via an exponential function: Nt = N0 x 10-kt N0 , Nt : number of bacteria, viruses at t= 0, t k : decay rate constant (day-1) For a decay rate k = 0.1 day-1, to reach 99.9999% reduction (“6 log-reductions”): Nt/N0 = 10-6 (or: N0/Nt = 106) 10log (N0/Nt) = 6 = kt à t = 6/0.1 = 60 days. With a travel speed for groundwater of 10 cm/day, then at 10x60 = 600 cm (6 m.) distance, we have theoretically reached above reduction in bacteria/viruses. 8.1.3. Case studies A) Gaza, Palestine (http://commerce.iugaza.edu.ps/Portals/20/Users/016/16/16/WATERS~1.PDF) The problems in this region are mainly connected to the limited water resources. The abstraction rates are amounted at a factor 1.5-3 times the natural replenishment rate of the acquifer. The overpumping of groundwater wells thus leads to sea water intrusion, and irrigation with this water causes soil salinisation. Typical chloride levels for drinking water wells in Gaza are > 200-1500 mg Cl-/L, much higher than the WHO standard of 250 mg Cl-/L. Nitrate levels > 500 mg NO3

-/L are reported, i.e. 10 times the WHO standard. Most of the irrigationwater in the Gaza area is reused, leading to high nitrate, chloride and pesticides levels.


Other sources of ground water pollution are: - domestic wastewater recharge, resulting into high pathogens, BOD, SS and nitrate levels; - fertiliser usage in intensive agriculture, again giving rise to high nitrate leaching rates. The above problems are enhanced by the unfavourable geology of the region (sandy bottom), in which transport rates of the ground water are much higher than in clayey areas. B) Nassau County, USA Here a serious ground water pollution has occurred since the early 1940, caused by a metal plating industry mainly discharging Cr6+ and Cd2+. At present, this has resulted into a pollution plume some 1300 m long, 300 m wide and 21 m thick (See Fig. 21). Typical values found in the ground water are: - > 10 mg Cr6+/L (with a WHO guideline for drinking water of 0.05 mg/L) - > 10 mg Cd2+/L (WHO guideline: 0.005 mg/L)

C) Groundwater wells protection in The Netherlands To avoid pollution of groundwater wells, the water authorities in The Netherlands have introduced a specific “zoning of land use restictions” (see below figure 22). Here we see stricter rules for land use and other activities close to the extraction wells: - First 30-150 m (catchement area): only water extraction activities are allowed - 1000-2000 m (protection area): strong restrictions exist with respect to

agricultural practices, housing, industrial and commercial activities, etc. - The remaining recharge area, with somewhat less stringent restrictions.

Fig. 21. Topography of the Nassau County study area, and Cr(VI) concentration isolines (mg/L) in the groundwater pollution plume (Chapman, 1996).


In many parts of the world, both in developed and developing countries, we see similar protection measures for water extraction points. Here, beneficial use is made of the natural degradation of the pollutants in the (slow-flowing) ground water. Fig. 22. Zoning for groundwater wells Protection in the Netherlands

8.2. Groundwater quality monitoring 8.2.1. Design of the monitoring network In the previous Units, we limited ourselves to the monitoring of rivers and lakes. Although groundwater monitoring is more complicated and time consuming than surface water sampling, we can basically follow the same “monitoring cycle” as described before. First of all, objectives have to be set for the groundwater monitoring. These objectives can, as in the case of surface water monitoring, be manifold, e.g.: • To assess and understand the general quality of the groundwater, as an aid to

optimal management of groundwater resources (ambient monitoring, operational monitoring).

• To identify locations of major pollution sources and the movement of pollutants in the aquifer (ambient monitoring, effluent monitoring).

• To determine the compliance with regulations and standards (effluent monitoring). • To determine the nature and impact of an accidental pollution event (early warning

monitoring). Before establishing a groundwater monitoring network programme, preliminary surveys should be made, lasting from a few months up to a year. The surveys include investigating the main features of the groundwater quality such as: pollutant sources, hydro-geological conditions, background values, and possible seasonal trends. Sampling during these preliminary surveys is nearly always limited to existing wells, boreholes and springs. The second part of the programme than entails longer-term groundwater monitoring in which the location and number of stations, sampling frequency and number of variables


is established. Here the aim is to minimise costs, at the same time still meeting the objectives of the programme. Number and location of sampling stations As indicated before, this will largely depend on the objectives of the groundwater monitoring programme, as well as on size and complexity of the area and financial limitations. In The Netherlands, for example, a national groundwater quality monitoring programme has been established, principally directed towards diffuse sources of pollution. The network comprises 380 stations (i.e. a relative high density of 1 per 100 km2), with emphasis on areas of importance for drinking water supplies. Compared to this, the density may still be higher (as in Germany: 1/35 km2), or, usually, much lower. This holds especially for larger and/or less developed countries. With respect to the locations of the sampling stations, existing wells for drinking water extraction are usually not the most suitable locations for most monitoring objectives (except for operational monitoring). Hydro-geological conditions such as groundwater flow rates and directions will be the main considerations in locating monitoring stations in relation to possible pollution sources; therefore much expertise is needed in these fields in order to establish a suitable monitoring network. The installation of specially constructed observation boreholes to specified depths, offers the best chance of obtaining samples that are reasonably representative of conditions in the aquifer. Construction procedures include drilling and installation of a well screen and filter, similar to the construction of extraction wells. Sampling frequency Sampling frequency will, amongst others, be a function of the type and objectives of the assessment programme, the nature of the groundwater body (e.g. its (in)homogeneity), and financial resources. Because of the generally long residence time and the relatively slow changes in groundwater quality, less frequent sampling is required than for surface water bodies. Thus, background and trend monitoring could be based on annual samples for large groundwater bodies and quarterly samples for smaller aquifers. (Much) more frequent sampling may be required for pollution source studies, especially if these are close to a potable water supply, and/or in case of rapid groundwater. Have a look at this (18 min.) YouTube movie to see how sampling is done: http://www.youtube.com/watch?v=7_5RcnaFn_w 8.2.2. Case studies Groundwater monitoring in Germany In Germany, the responsibility of groundwater monitoring lies within the 16 Federal States (Länder). The monitoring scheme consists of three types: • Basic or reference monitoring stations, for trend detection, control for compliance

with standards, impact assessment, etc. • User related (operational) stations, especially for drinking water (also as early

warning) • Emission related monitoring (agriculture, waste dumps, etc.).


The measured variables basically follow the GEMS list (Table 1). Depending on preliminary surveys it may then be decided to either reduce the number of parameters in the routine monitoring, or include additional parameters such as heavy metals, organic micropollutants, etc. In Germany, the frequency for monitoring the baseline and trend stations is 2-4 times per year. Groundwater pollution due to a waste dump in Toronto, Canada In this case, land filling of municipal and industrial waste took place over the period 1940-1976. At the end of this period, the landfill covered 5.4 ha, with a thickness of 5-10 m. A preliminary survey showed that a pollution plume extended about 700 m. north of the landfill, in the direction of the groundwater flow. The zone of contamination was separated by a clay and silt layer from a deeper aquifer, which was used for water supplies. In the extensive monitoring programme, it was decided to construct multi-level groundwater sampling points to enable regular water samples to be taken from many depths. As a simple indicator for the spread of pollutants, the non-reactive Cl- ion was chosen; its spread indicates the maximum possible transport rate of pollutants (see Fig. 23).

Action List for Unit 8 • Look and listen to the PowerPoint presentation available under “Lecture”.

YouTube illustrations • Movie (18 min.) on groundwater sampling http://www.youtube.com/watch?v=7_5RcnaFn_w Further Reading

• Chapman (1996), Chapter 9 • Groundwater monitoring in the European Union Water Framework Directive: see Additional material Course 3.2. • UN/ECE Task Force on Monitoring & Assessment (2000), available at: http://www.unece.org/env/water/publications/documents/guidelinesgroundwater.pdf

Fig. 23. Cl- contours in groundwater under a waste dump, Toronto, Canada (Chapman, 1996).


Unit 9 - Cost aspects of monitoring 9.1. Cost of a monitoring programme In this Unit we will have a look at main aspects related to costs involved in monitoring. “Water quality monitoring” constitutes the efforts undertaken to obtain quantitative and qualitative information on the physical, chemical and biological characteristics of water. Similarly to other investigative activities, the monitoring of water quality involves the spending of resources (costs), necessary to achieve the final programme goals. Thus, by costs we refer to the burden sustained in order to perform a certain activity, to accomplish certain production activities, or to achieve certain goals. It is the value of money that has been used up to produce something, and hence is not available to be used again. In water quality monitoring activities, costs refer to the total expenses burden from the desk studies up to information dissemination to the final users; these are all required costs for the monitoring activities. Required costs are those expenses each monitoring study will incur. The total monitoring costs will depend on the number of study sites and sampling stations required. Shared costs are for items which are often used infrequently and could be shared between different groups or projects. The implementation of a monitoring programme requires access to resources, including a well-equipped laboratory, office space, and equipment for field work, transport and the availability of trained personnel. In addition, factors such as sample collection, analytical services and reporting should also be considered. Thus, the minimum cost of any monitoring activity is determined by the purpose of the programme (surveillance, operational, investigative – refer to previous units for further details on monitoring types and objectives). The costs involved in monitoring activities generally consists of the following:

• Equipment and maintenance - equipment, parts, man-hours • Sample collection and shipment - man-hours, shipping costs • Analysis - cost of analytical services • Results - man-hours (data review, analysis, filing)

The total cost of a network operation is thus build up by:

• the costs of field visits, sample collection, discrete sample collection and other maintenance needs;

• the costs of analytical determinations in the laboratory or measurements by field monitoring instruments (equipment rental/purchase); and;

• the costs for data-processing, including database maintenance and reporting. The cost of a particular component is generally given by the specific frequency of the activity multiplied by its unit cost. However, the component and unit costs generally should cover not only the direct expenses but also some amortized recovery of capital investments associated with each component and all other indirect expenses. As a rule of thumb, once a programme has been developed and implemented, it is relatively inexpensive to expand the spectrum of analyses as compared to the field portion of the costs for new programme. This is because usually the same effort that is used to collect samples for several parameters is the same as needed to collect


samples for one or two analyses. With this type of programme expansion, care must be taken that the initial purpose of the programme is not compromised. Inadequate planning often leads to vastly increased field time and cost because of continuous repairs, resampling, data retrofits, and eventual revamping of the entire sampling station design. If a company has several monitoring sites in various places, expenditures spent in this manner can be quite significant. To avoid this problem, one needs a clear focus and well-defined monitoring purpose combined with wisely spent money, experienced consultation, and proper equipment. Some of the pitfalls that increase cost are:

• Lack of careful planning • No distinct objectives • Inappropriate equipment • Erroneous programming or alteration of the programming • Lack of systematic maintenance • Change in focus which is not carried all the way to the instrumentation, and • Incompatible add-ons.

All of the above also increase the data analysis time due to mismatched or missing data. While the system design directly influences the operational costs, the work required to analyse the data is often ignored in initial cost assessment. This may be due to the lack of a defined purpose for the program, or because the data collection programme is meant to solely meet the needs of a government agency. In designing a monitoring program, this is not sufficient. The data resulting from the sampling should be the reason the programme was initiated in first place. In any monitoring program, the receipt and review of the data are the most important of all of the factors to be considered. Where the importance of the monitoring is acknowledged, it is not uncommon for a manager to spend a considerable amount of time reviewing and analyzing the data that is collected.

Cost should not be the only consideration in a monitoring programme. Careful systematic planning when it comes to water monitoring is essential. While the initial dollar figure is meaningful, one must remember that it will (in most cases) be the least of the total expenditures. Inappropriate, poorly constructed equipment may waste manpower and effort. To avoid some of the common pitfalls, the process of the programme design should consider the following:2

1. Determine the general needs and have a written statement of the monitoring programme purpose.

2. Determine whether monitoring can provide all or part of the necessary information. Describe the information needed.

3. Make a good faith estimate of the equipment and operational costs according to specific situations (costs varies according to objectives and network).

4. Determine the need for additional information to be combined with monitoring data such as purpose, collection method, intervals, etc. 2 Boman, B.; Wilson, C. and E. Ontermaa (2008). Water Quality Monitoring Programs for Environmental Assessment of Citrus Groves. Circular 1407, Agricultural and Biological Engineering Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Available at http://edis.ifas.ufl.edu. Sanders, T.; R. Ward; J. Loftis; T. Steele; D. Adrian and V. Yevjevich (1983). Design of Networks for Monitoring Water Quality. Water Resources Publications. Colorado.


5. Decide how the monitoring data are to be collected. Have a written statement that specifies the degree of automation, frequency, and sampling sites.

6. Determine what data is needed and why it needs to be collected. Record the specific details of the analysis and characterization processes.

7. What are the requirements for data validity? Begin to establish a QA/QC (quality assurance/quality control) programme, including sample preservation, storage time, and collection method (additional information may be collected at local certified laboratories).

8. Determine what equipment is needed, what it is supposed to do, and how the equipment functions. Determine type, cost, configuration, maintenance needs, and tolerance to the environment.

9. Speak to the analysis laboratory and other service providers to clarify their role, what items they will provide, how they will perform the analysis, and how much it will cost. Determine whether a contract is needed.

10. Develop a record system and a written description of the programmes and their purposes.

11. Establish a maintenance schedule in writing. Provide time for test runs and record problems, needed improvements, etc. 9.2. Optimisation of Water Quality Monitoring Networks Water quality monitoring should consider specific information and data requirements from stakeholders (watershed managers, policy makers, scientists, communities and civil society, NGO’s and other water users). Statistical optimization of a monitoring programme is essential to increase monitoring performance, while minimizing the costs. However, optimization is rarely achievable, if ever, possible at the start of the programme, since it would require a large amount of knowledge about the statistical characteristics of the variables being monitored; such information is almost never available at the design stage. Even when historical data is available or when a network has been in operation for some time, it is probably more reasonable to talk about improving system performance than optimizing it. Generally the performance optimisation of water quality monitoring networks is related to the collection and generation of the same amount of information required for decision making process using less financial resources In that sense, to improve performance of a monitoring network, research is needed to determine how much data is adequate. Performance optimization requires an objective function relating information and costs. Optimization cannot be incorporated in the design of a monitoring network unless there is a specific management use of the data with the associated benefit of avoided costs. The primary goal of an optimisation process is to simplify parameter schedules and therefore to save resources. This can be done by providing screening information to determine appropriate parameters to be sampled and also by identifying indicator parameters that are easy to measure and interpret. Finally relevant data to end users is produced and the efficiency and performance of the monitoring programme is increased.


Past experiences on this matter have been reported in many locations (Sanders et al., 1983; Breukel et al., 2001 (MTM-3; see additional material Course 3.2). As an example, the network optimisation programme at the IJsselmeer area (the Netherlands) revealed after statistical research, that higher sampling frequency (12 times a year) at less locations (50% less) provides more information than a lower frequency at large number of locations, and reduces the cost by 35-50% (see Breukel et al., 2001); cf. Fig.15. In the same case it was advised to select parameters which could be analysed with the same analytical method/run to allow a cost-effective operation of the laboratories. As stated before, the major constraint for the application of any of the above techniques is the availability of complete data sets on water quality for all the monitored stations. Thus, a first sampling stage with dense monitoring stations should be undertaken in order to collect more data (Nunes et al., 2005). After determining the spatial covariance of those stations, the performance optimization of the water quality monitoring network can be recommended. Action List for Unit 9 • Look and listen to the PowerPoint presentation available under “Lecture”.

Further Reading • Book Bartram and Balance (1996) • Breukel et al., 2001 (MTM-3) • Nunes, L. M.; S. Caeiro; M. C. Cunha and L. Ribeiro (2005). Optimal estuarine

sediment monitoring network design with simulated annealing. Environmental Management 78, 294-304 (see additional materials; quite complex!)

course 3: water quality monitoring and assessment

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