Water clarity in lakes and reservoirs - Essay Example

Water Clarity in Lakes and Reservoirs Introduction The National Resources Defense Council asserts that an increasing number of Americans are open to the elements of tap water contamination at levels over those set by U.S. Environmental Protection Agency standards. According to a survey conducted in 1999 by the Water Quality Association, around sixty percent of adults consider that the quality of water they are drinking affects their health, and about three-quarters have distresses regarding the quality of their household water supply. Contrary to popular belief, crystal clear water is not necessarily the true measure to which all lakes should be compared. It is also not entirely true that lakes with low levels of visibility and transparency are due to pollution or degradation in water. Another common belief is that clearer water is safer to swim in or to drink which is also not entirely true. On the contrary, clear water may likely be just as filled with pathogens, bacteria and other contaminants that could be harmful to human health as cloudy water is generally perceived to be. The water treatment experts at Amway Corporation laid down suggestions regarding the following tests and resources for beneficiaries who would want to know if their drinking water is safe: 1) Look at it. Water should look clear and have no floating particles. 2) Smell it. Water should be free of unpleasant odors. 3) Taste it. Water that tastes unusual should be tested. 4) Contact the local health department to have the water tested if it looks, smells, or tastes unusual. 5) Request a copy of the Consumer Confidence Report from the community water supplier. (Journal of Environmental Health, 2000) This paper covers issues related to water clarity, what it is, how it is measured, what causes clarity problems and how to tackle such problems Literature Review Water clarity can be defined as a measure of the amount of sunlight that passes into the water and reaches the leaves of underwater grasses. Water clarity can be termed as dependant on three factors; proper water chemistry, sufficient and effective filtration, and good circulation. (Pool Chlor, 2006) Water chemistry relates to the alkalinity levels within water. In case these levels are out of balance, the result can be in the form of turbidity. Turbidity is the cloudiness caused in water because of suspended or dissolved material. It can also be said that insufficient chlorine in the water, small, perched algae and bacteria can result in turbid water. (Pool Chlor, 2006) How to Measure Water Clarity Measurement of water clarity is quite helpful in monitoring any changes in water componential balances and enables communication for these changes to concerned persons. One common method to measure water clarity is by the use of a disk, more commonly known as the Secchi disk. A Secchi disk is by far the simplest, standardized instrument used to determine water clarity. "It is an 8-inch (20 centimeter) diameter, black and white disk attached to a dowel rod, PVC pipe, rope or chain. Inch or centimeter intervals are marked on the rod, pipe, rope or chain with permanent ink, paint or clamps. Ideal clarity for aquatic plant production is generally greater than 36-inch visibility" (Porter, 2002) The measurements taken by the use of Secchi disk are likely to be quicker through the use of rod or pipe as against a rope of chain, except when water is very clear, in which case, an extremely long rod or pipe may be required. When measuring water clarity, the date of measurement, the measurement itself and the source of turbidity, usually sediment (brownish muddy color), phytoplankton (greenish color), humic stain (tea color from decaying leaves or plants) or some combination of these, should be recorded for reference purposes. Secchi disk measurements are mainly precise when taken on comparatively still, sunny days, preferably during the middle of the day from a dock or some sort of floating mechanism such as a boat, float tube, air mattress or life preserver. (Porter, 2002) Several other devices are also used by scientists to measure turbidity, light extinction, and spectral analysis related to water clarity, however, Secchi disk is widely considered as one of the oldest, easiest and most economical method for measuring water clarity. To determine a lake's Secchi depth, the disc is lowered into the water to find the depth at which it first vanishes from the observer's sight. On occasion, the Secchi disc can still be seen as it rests on the lake bottom, or it may disappear into thick submerged aquatic macrophyte growth. (Robert, 1998) What Affects Water Clarity Generally it is considered that differences in water clarity are primarily caused by the presence or absence of dissolved substances and suspended particles in the water. However, to fully comprehend the dynamics of how dissolved substances and suspended particles affect water clarity, consideration needs to be given to some factors. Dissolved organic substances or compounds can appear from many forms of terrestrial and aquatic plants, and may cause the color of the water to become reddish or brown, at times even to the extent of making it appear completely black. In case there are plenty of dissolved organic compounds in the water, scientists frequently refer such water as being "colored" or occasionally they'll refer it as being a "dark" lake. "Particulates include free-floating algae, called phytoplankton, as well as other solids suspended in the water. These include sand, clay, or organic particles stirred up from the bottom, washed in from the shoreline, washed in from the surrounding land, or brought in by the wind and rain." (Florida LAKEWATCH, 2002) Since particulates within water take up and disperse sunlight as the light go by through the water, Secchi depth values decline as the quantity of particulates in the water increases. Although all particles are recognized to affect water clarity, studies throughout the world have revealed that free-floating algae are the focal form of particles that affect water clarity in most lakes. (Florida LAKEWATCH, 2002) Regulations Governing Water Clarity Regulations governing the quality of water dispersed by community water systems are basically laid down by the U.S. Environmental Protection Agency (EPA). This agency makes it mandatory to standardize national upper bounds, or maximum contaminant levels, on the absorptions of organic and inorganic contaminants within the community drinking water supplies. According to a study, around ninety substances are currently being synchronized, and this number is expected to grow in accordance with the regulatory plan detailed in the 1996 Safe Drinking Water Act Amendments (PL 104-182). For each rule that was proposed, the EPA is under the obligation to issue a regulatory impact assessment (RIA) report that evaluates the estimated costs of advancement of treatment facilities to the estimated health benefits of reducing exposure. The preliminary post amendment regulatory action has paid more attention on separate rules for single contaminants such as arsenic and radon, as well as rules for groups of comparable contaminants. Each of these contaminants or groups of contaminants is taken care of in segregation from a regulatory viewpoint, with autonomous RIA's recently performed for each rule. Water systems will be forced to fulfill consecutively with each rule as it is disseminated. (Small et al., 2004) Because the performance of RIAs is being done sequentially, accordingly disregarding contaminant co-occurrence, treatment interactions and overlaps, and probable joint health effects, they may not replicate the realized costs and benefits for the collection of rules. Moreover, the sequential regulatory approach has been generally criticized on pragmatic grounds against these substantive issues. Community water systems generally have only inadequate resources to supplement treatment technologies. Most systems are no so large, serving not more than a few thousand people, and thus financial restraints state that sweeping treatment changes can hardly be made frequently. Yet, the present regulatory protocol is capable of producing fresh standards in sequence, which may impose an infeasible series of treatment upgrades in the worst of cases. The Case of Crater Lake Crater Lake has long been famous for its astonishing water clarity and intensely blue color. During August 1937, Arthur Hasler from the University of Wisconsin lowered a 20-centimeter diameter Secchi disk into the lake on three different days and observed that it disappeared at depths of 36, 39 and 40 meters. By comparison, Secchi disk transparency of other lakes was considerably less, ranging between 1.5 and 20 meters for 72 lakes tested. (Larson 2002) However, readings obtained during summer 1978 showed that the clarity of Crater Lake was probably diminishing. Findings were reported to the park service in October 1978, highlighting that the data were particularly preliminary but admonition of possible optical deterioration was also laid down. Unluckily, historical data for Crater Lake were scarce, amounting to a small number of reliable measurements. Thus, it was practically not possible to distinguish whether the 1978 data represented a long-term downward trend or a short-term downward fluctuation. But later on, 46 additional readings obtained from 1979 through 1984 reinforced the notion that clarity had diminished. Upon concerns by researches and authorities alike on the lake's decontamination, perhaps irrevocable, an observatory was set out to determine whether sewage was reaching the lake. In 1983, it was discovered that one of the springs emerging along the caldera wall and flowing into the lake contained roughly 10 times more nitrate-nitrogen than any of the other 40 to 50 caldera springs tested. Using maps and other geological information, it was made possible to determine that this spring was linked to an aquifer flowing directly beneath the septic tank-drain field system. It was later deduced in the light of newly discovered facts that septic wastewater was infecting through drain field soils into the aquifer. Even though it was strongly recommended at the time that a dye-injection study be conducted to trace the pathway of wastewater through underlying soils and rock, the work was never attempted. As a result, the question of sewage contamination in Crater Lake was never completely resolved. Faced with other evidence, nevertheless, the park service approved in 1987 that sewage was possibly entering the lake. In 1991, 13 years after first being alerted to the possibility of sewage contamination, the park service detached the septic tanks from the edge and sidetracked the sewage through a new $3 million pipeline. Since then, lake-water clarity has seemingly enhanced: In 1997, park service limnologists reported utmost average summertime visibility depths of 41.5 meters with a 20-centimeter (diameter) disk and 49.2 meters with the 100-centimeter disk. But whether this optical enhancement is because of sewage diversion is still not clearly known. (Larson 2002) Significance of the Project Suitable water quality is primarily vital for fish and aquatic plants, and muddy water limits production of both. Fish typically perform well in clearer water when substantial aquatic vegetation is there. Water clarity is also something of great importance to many people. General public judge water quality by what they can see, as in clearer water, and so their assessment is often based on this standard. For example, lakes with very clear water may be supposed as good, unpolluted, or pure. On the other hand, lakes with limited clearness may be described as undesirable, polluted, or degraded. Significant and Current Water Quality Issues The media reported that 40,000 aeration systems were discharging untreated waste water into homeowners' backyards, although the exact number of such systems was unknown, as were their operating conditions. Installation permit records were not complete. While citizens worried about disease and pollution, an OEPA connection ban and class action lawsuit put the Hamilton County Board of Health in a reactive mode. There was a rush to inventory and evaluate the operating status of all existing aeration systems first. (Goodman et al., 2004) The water codes governing almost all the western states including some state constitutions contain the term "beneficial use of water." Constitutional treatment of beneficial use vary from straightforward statements declaring the right to suitable water for beneficial use, to more normative provisions which necessitates reasonable and non-wasteful water use. Some statutes of around nine states chant in almost matching tone that "beneficial use, without waste, is the basis, measure, and limit of a water right," and things which remain refer in some way to beneficial use. Some states exclusively identify or register certain uses as beneficial, either in the constitution or in statute. For example, the Idaho Constitution recognizes agriculture, mining, milling, power, and domestic purposes as beneficial. Texas statutes list as valuable uses agriculture; gardening; domestic uses; stock raising; mining; manufacturing; industrial and commercial uses; recreation; pleasure; and oil, gas, and .sulfur production. States that record explicit beneficial uses in statutes in general began with a fundamental list years ago, giving coverage to the late nineteenth century needs of domestic use, farming, and some industry, and then supplemented their statutes over the period of time to add in more "contemporary" purposes, such as in-stream uses for amusement and fish and wildlife. In other words, statutory expressions of valuable use have altered to imitate changes in values and changes in scientific understanding. Still, these lists are commonly construed as nonexclusive Conclusion From the example of Crater Lake, it can be inferred that water clarity level can be related to contamination of water reservoirs. Although this conclusion was never established within the example, it still appears to be the most likely cause of reduced water clarity. If we simply accept the idea that it truly does depict a contamination, it becomes further relevant that water clarity is in fact directly related to such issues. Thus, any measure or research in line with the ones carried on Crater Lake might prove a lot feasible to provide decisive grounds to improve quality of water through enhancement of water clarity. Some of the proposed ways to reduce cloudiness of water include fencing to exclude livestock, planting of aquatic vegetation, fertilization, alum application and gypsum application. When trying to observe water turbidity changes, Secchi disk measurements should start before such treatments and be measured at least monthly or quarterly until clarity improves satisfactorily. Filters can also be used to remove suspended solids from the water. Solids may not necessarily be large enough, like leaves, twigs and debris, to see through naked eye. There may be such solids which are so small that millions of them are required for to make a pool of water appear cloudy. Filters are useful in removing any of these solids. However, filters cannot remove substances which are dissolved with water. Such substances actually become part of the water itself. For instance, dissolved metals such as copper or iron can tint the water aqua or tan, but remain dissolved and thus beyond filtrations. (Pool Chlor, 2006) The time it takes to clear dirt, algae, bacteria and other suspended solids from water strictly depends on the type of filter. The way filter is maintained, the amount of time it runs and the circulation within water are also some factors for water clarity through filtration. If the filter is properly sized according to the size of the pool, and with everything working right, filters are capable of maintaining a clean pool clean. However, they may differ radically on their abilities to clean a dirty pool. In order for the filter to remove solids from all of the water, the water must be kept under circulation from "top to bottom" and "round and round". Circulation patterns are considerably influenced by the shape of the pool, the locations of the drains and returns, and the strength of the return water flow. Pools should be designed and function in a manner which eliminates "dead spots" of un-circulated water. (Pool Chlor, 2006) Works Cited (2000) A Six-Step Test of Drinking-Water Safety and a Countertop Filter. Journal of Environmental Health. 10, 41. Florida LAKEWATCH (2001) A Beginner's Guide to Water Management - Water Clarity. Publication of Florida LAKEWATCH Florida LAKEWATCH (2002) Measuring Water Clarity. Publication of Florida LAKEWATCH. Larson, D.W., (2002) "Probing the Depths of Crater Lake: During Much of Its 100 Years of National Park Status, This National Treasure Saw Little Scientific Study, despite Significant Environmental Threats". American Scientist, 1, 64. Neuman, J.C., (1998) "Beneficial Use, Waste, and Forfeiture: The Inefficient Search for Efficiency in Western Water Use". Environmental Law, 4, 919. Schervish, M.J., Small, M.J., (2004) "Analysis of Contaminant Co-occurrence in Community Water Systems". Journal of the American Statistical Association, 465, 45. Porter, M. (2002) A Secchi Disk is Used to Measure Water Clarity, Wildlife. Roberson, J. A., and Power, J. A. (2000), "The Groundwater Train Wreck," Journal of the American Water Works Association, 92, 8 and 103. Robert J. D., (1998) Measuring Water Clarity with a Black Disk. Limnology and Oceanography, pp. 616-623 Royle, J. A., and Berliner, L. M. (1999), "A Hierarchical Approach to Multivariate Spatial Modeling and Prediction," Journal of Agricultural, Biological, and Environmental Statistics, 4, 29-56. Travis Goodman, Terry Hull, Tim Ingram (2004) "On-Site Wastewater Management - an Integrated Approach to Improving Water Quality and Preventing Disease". Journal of Environmental Health, 2, 21. Utterback, C. L., L. D. Phifer and R. J. Robinson. 1942. Some planktonic and optical characteristics of Crater Lake. Ecology 23:97-103. Pool Chlor. (2006) Water Clarity Will Focht (2002) "Assessment and Management of Policy Conflict in the Illinois River Watershed in Oklahoma: An Application of Q Methodology". International Journal of Public Administration, 11, 1311. Read More