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Copy and Paste This Permanent Link:http://www.stormh2o.com/october-2008/cobb-county-monitoring.aspx

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Biologist with "fixed" DO sample

In my article in the September 2008 issue of Stormwater, I described Cobb County, GA’s municipal in-stream water-quality sampling program and how it is “gratifyingly comprehensive,” promoting regulatory accountability. After a recent water-quality excursion down Atlanta’s Chattahoochee River corridor, I was struck by a whimsical quotation’s nagging relevance to the comprehensive part of that equation, to the eyefuls, awefuls, and incidents of our muddling odyssey. It was not the first time my monitoring efforts were mocked by the chastising irony of “nonsense” rhyme, and a clearer perspective of reorganized reality.

In the soliloquy from Lewis Carroll’s Through the Looking-Glass, we are called to consciousness (or incomprehension), by the Walrus: “‘The time has come,’ the Walrus said, to talk of many things: of shoes and ships and sealing wax, of cabbages and kings, and why the sea is boiling hot, and whether pigs have wings.” Indeed, the Walrus’s words anticipated environmental boating foibles and ironies we experienced on our cruise, as we often speak of the relative stability of our good ship, the overloaded fishing canoe we swamped without overturning, of our inappropriately casual shoes’ reluctance to return to a dry state, of the sealing wax or lamination that would have preserved my GIS ink copy maps from wet destruction, of the cabbages, other garbage, and trash apparently native to that stretch of urbanized watershed, of the regulatory “kings” that casually commissioned our voyage of the darned, of the turbid and low flowing river’s “boiling” hotter than usual, and yes, whether the pair of feral pigs we saw scamper up the riverbank at greater than pig speed indeed had wings.

Ultimately, once “dried out,” wild water adventures are even more gratifying to the experienced environmental regulator, as their incidence initiates successful apprehension of the many problematic things for which the time often comes to speak, and stand accountable.

Specifically, although chemical sampling and chemistry per se can conjure up things like that junior high science project, “The Wonder of Rust,” or, perhaps, the rousing 14-step Michaelis-Menten proof in senior kinetics, the ideal surface water work-a-day grounds us in practical encounters assessing the physical and chemical natures of water as they influence specific systems of examined aquatic organisms. These encounters are coveted by freshwater stakeholders, from citizen volunteer to environmental field tech to scientist, by those who care to comprehend, and by those who are called at times to speak of many things.

The Physical Properties of Water: What Wet Means
Renaissance Molecule. It behooves us to discuss the versatile physical nature of water as the distribution and success of organisms. The “structural, physiological, and behavioral characteristics displayed by animals living in various habitats” (Pechenik 2000) depend on water’s fluid, solvent, bonding, density, and heat-conveying characteristics. We include temperature and conductivity in the discussion of things characterizing water’s “renaissance molecule” physical nature.

Intuitively, we grasp that water is wet, and so facilitates direct, uncomplicated gas exchange without the risk of desiccation across body walls or gills, vascularized extensions of body walls. Fertilization and development can occur completely and simply in the aquatic environment because many invertebrates freely shed gametes and embryos, unhindered by desiccation and terrestrial-complex systems required to prevent it. Metabolic byproducts like ammonia can be excreted through the body wall of aquatic dwellers into immediate dilution, relinquishing the energy demand and complexity of terrestrial excretory systems. Ammonia is particularly toxic to cellular respiration processes.

Water is a versatile solvent, and invertebrates of all sizes and their embryos can derive soluble organic nutrients and salts by direct uptake. In addition, “as an indirect benefit to aquatic invertebrates, suspension in a nutrient-containing, wet medium permits primary producers to take the form of small, (typically less than 25 µm [micrometers]), suspended, single-celled organisms (phytoplankton); roots are not mandatory. Phytoplankton cells can attain high concentrations in water, and can easily be harvested and ingested by many suspension-feeding aquatic herbivores, including the developmental stages of many invertebrate species” (Pechenik 2000).

Water is denser than air, and it supports structures in small organisms that would collapse on land, such as gill filaments. Water’s density even precludes the need for a skeleton in some organisms. For the same reason, organisms move more efficiently in water, expending little relative energy as buoyancy compensates for gravity. Some invertebrates don’t move at all, feeding on suspended phytoplankton, zooplankton, and dissolved nutrients flowing past in the dense, rich soup. Indeed, this lifestyle “seems to have been exploited only by web-building spiders in the terrestrial habitat” (Pechenik 2000). Fertilization and development are also served by water’s density; external fertilization occurs simply and with little energy expenditure as sperm and egg are suspended in a great nutrient-suspended wet womb.

The specific heat of a substance is defined as the number of calories required to heat a gram of the substance one degree Celsius. Hydrogen bonding increases the specific heat of water because the inherent polarity of the water molecule results in charged regions that create an attraction between molecules. For water to evaporate, these bonds must be broken, and their strength allows water to remain a liquid at room temperature when it would otherwise quickly evaporate. Slow to heat up, then, it is also slow to cool down, as so much quantitative heat has to be drawn off. Water temperatures for reasonably large bodies can vary as little as a couple of degrees Celsius in air temperature fluctuations of 20 degrees Celsius. Reasonably, “Invertebrates living in thermally variable (terrestrial) environments require biochemical, physiological, and/or behavioral adaptations not required by organisms living in more stable, aquatic environments” (Pechenik 2000).

Hydrogen bonding in water also accounts for its relatively high surface tension; the sum of intermolecular attractions on all sides of interior molecules cancel out, but surface molecules are pulled outward and downward because there is negligible attraction above them in the other medium. The forces are balanced by resistance to compression. This creates a tight, conservative, smaller surface, with resistance to releasing more molecules to the surface than the compression resistance force demands. Considering energy balances, it costs energy to break bonds and have interior molecules in freer, higher (potential) energy states at the surface bound to fewer interior molecules, so as many stay in the interior as compression resistance allows. The sphere is a surface area saving three-dimensional shape. The Hemipteran “water strider” in the family Gerridae takes advantage of surface tension as the potential energy of its settling mass is lowered yet resisted incrementally by the increase in surface area and potential energy of elastic water surface tension forces.

Bridge Barely Over Troubled Water. There are problems associated with aquatic living as well. Environmental professionals are tasked in testing, regulating, and educating to control physical and chemical pollution of inherently vulnerable fresh water and in “checking” flows of troubled water under lapsing bridges of public trust.

For one thing, light diminishes quickly in water, so photosynthesis-dependent primary-production (fixing of carbon from carbon dioxide into carbohydrates) organisms, such as algae and phytoplankton, are limited after 50 or so meters. Turbidity reduces this amount.

In addition, oxygen’s saturation of and diffusion through water are much more limited than in air. In fact, water’s oxygen capacity per volume is about 2.5% of air and oxygen moves at least 300,000 times faster in air than in water. This significantly contributes to biota dissolved-oxygen (DO) sensitivity, which is discussed later. Even slight water movement, however, significantly enhances oxygen exchange, and many sessile organisms live in high-flow areas or have adapted to create flow themselves. In my article in the September issue, I talked about case-making caddisflies undulating in their cases to create flow and augment DO uptake.

Water is 800 times denser than air and 50 times more viscous; this creates drag for larger organisms and viscosity hindrance for smaller ones. Reynolds numbers for small organisms measure inertial forces against viscous ones, and are represented by Re = vLp/η, where v = speed, L = length, p = density, and η is the coefficient of viscosity. Temperature decline can increase viscosity, and, illustrating how critical this can be, smaller organisms live “in a world in which there is really no such thing as ‘gliding’ to a stop; as soon as propulsion stops, the animal stops” (Pechenik 2000). For example, in those circumstances, rake-shaped filter appendages act like paddles, and water runs around rather than through them. Obviously, at low temperatures, microinvertebrates are even more sensitive to other factors, manmade or otherwise, enhancing already precarious viscosity.

Nutrient sampling in midstream

Pollutants are soluble in water as well, and the smaller the organism, the higher the surface-to-volume ratio and diffusion of pollutants across greater relative body wall areas. Because free-living larva and embryos are so small and are in complex, critical developmental stages, degrees of pollution insult can occur at one-tenth to one-hundredth the pollution concentration impacting adults of the same species. Because freshwater organisms, especially, are hyperosmotic (of higher solute concentration than surrounding medium), they have to develop mechanisms for expelling water (since structures like gills are so permeable) and for reclaiming salts. In addition, because salts dilute in freshwater, they have to be supplied to the egg by the parent. Contrastingly, marine embryos obtain salts required for growth and differentiation easily in the saltwater environment.

Saltwater easily maintains the bicarbonate ion, and the pH stays around 8.1, whereas freshwater environments have less buffering capacity, and organisms can be subjected to pH swings; buffering and pH effect will be discussed in the next section.

Water conducts an electrical current in the presence of ions; conductivity is assessed with a handheld meter at each site. Conductivity levels are dependent on ion concentration, mobility, and valence. Inorganic compounds such as salts from industrial processes and wastewater are good conductors and alert sampling personnel with high readings, whereas organic molecules do not disassociate readily in aqueous solutions and cannot accurately alert environmental evaluators through conductivity. Conductivity is reported in microSiemens/cm.

Temperatures recorded during chemical sampling help stream biologists to understand chemical and biological sampling findings for a site; temperature drives biological processes like growth, DO uptake, and metabolism, as aquatic dwellers are essentially ectotherms, drawing heat from the environment, and thriving only within specific temperature windows. Temperature is influenced by flow, depth, stream canopy, water color, time of day, and season. One anthropogenic contribution to temperature is the establishment of more impervious surfaces; hot pavement flows in rain events cause significantly acute and intermediate-term higher stream temperatures.

The Chemical Properties of Water: Chemistry Is Fluency
“Some water quality factors are more likely to be involved with fish losses such as dissolved oxygen, temperature, and ammonia. Others such as pH, alkalinity, hardness, and clarity affect fish, but usually are not directly toxic. Each water quality parameter interacts with and influences other parameters, sometimes in complex ways” (NRAC 1993).

Now that we have discussed the physical nature of water as it regulates the distribution of aquatic life, let us explore the ways in which physically influenced chemical parameters are critical to sustaining specific systems of distributed aquatic life forms, and how comprehensive chemical stream monitoring commands fluency in the many things of that fluid world.

Caution: Oxygen in Use. Cobb County municipal in-stream monitoring chemical sampling assesses several physical and chemical characteristics of streams, and dissolved oxygen is among the most critical for sustaining aquatic life, bearing considerable discussion.

Increased temperatures drive DO down. Technically, in ΔG = ΔH = TΔS, the positive change of entropy of gas expansion serves a spontaneous, negative ΔG when T is high, but the negative change of entropy associated with oxygen dissolution and its lower energy ordering by pocketing in water spaces brings the ΔG down into less spontaneous, if not unspontaneous, positive numbers, especially at high temperature. Indeed, there is a net release of heat upon oxygen pocketing that is similar to water release of heat at solidification, upon attaining ordered, lower energy states; this is discouraged by higher temperatures, predicted by ΔG = ΔH – TΔS, and borne out in measured DO at higher versus lower temperatures.

Dissolved oxygen is both produced and consumed. Because photosynthesis produces oxygen during the day, and respiration by plants (the “dark reaction”) and animals consumes it at night, DO especially in ponds is highest in the late afternoon and lowest at dawn; many low photosynthesizing streams’ DO levels are low-temperature-driven and are higher at night. Also, agitation over rocky “riffles” introduces oxygen into streams, and sensitive macroinveretebrates thrive there; DO levels determine how macroinveretebrates, microbes, and fish are distributed. Higher atmospheric pressure drives oxygen into solution. Dry periods’ low flows cultivate and carry less total DO, because there is less surface for atmospheric diffusion. DO concentration can be affected, too, because less DO-enhancing riffle area is advantaged and DO-sponsoring higher flows are down. Biochemical oxygen demands from bacteria, especially in wastewater, and chemical oxygen demands of oxidizable organic compounds in the water can pull down DO levels. Cobb County tests for both, and these are discussed later. Turbidity, also discussed later, can block light, restrict photosynthesis, and thus limit oxygen production.

Cobb County stream personnel follow the Winkler method for DO collection and analysis. A 300-milliliter glass bottle is submerged in the high flow of the stream, with care not to allow water to lap vigorously in, creating an aerating effect. Two milliliters each of manganous sulfate and then alkaline iodide azide is added, “fixing” the dissolved oxygen in the sample as it forms manganic hydroxide MnO(OH)₂ with the manganese. Sulfuric acid is then added, and the manganic hydroxide forms manganic sulfate Mn(SO₄)₂, which acts as an oxidizing agent and frees iodine from the azide potassium iodide. At the lab, once titrated with thiosulfate, the iodine is stoichiometrically equivalent to the O₂ originally present.

DO is reported in milligrams per liter and then compared with DO saturation for the recorded temperature so that the result can be effectively judged.

S.C.U.B.B.A. One compelling example of gas solubility’s impact on aquatic life involves the diving beetle Dytiscus as it captures a bubble at the surface and fastens it over a spiracle breathing aperture, enabling it to stay down and predate for some time. Waste CO₂ in the bubble diffuses into the water because it is fairly soluble, pulled into solution in order to maintain equilibrium in the conversion of CO₂ to H₂CO₃. Nitrogen in the bubble is not very soluble in water and stays in, maintaining physical integrity; it is lost slower than oxygen is gained, drawn in from the water to reestablish the original atmospheric ratio of oxygen to nitrogen lowered by respiration. A few other insect divers advantage gas solubility differences as they predate with a “Self-Contained Underwater Bubble Breathing Apparatus.”

OH: Dance with Protons. Recorded midstream with temperature, pH critically influences most aspects of aquatic life as it influences and is influenced by water chemistry. Levels below 4.5 or above 10 cause mortalities. Crayfish shells become soft at low pH, because they are composed of calcium carbonate and react with acid. Suboptimal pH levels can be caused by acid rain water, naturally acidic soils, and poorly buffered water, discussed later in this section.

In addition, pH levels for freshwater (especially ponds) vary from low levels at night when carbon dioxide produced in vegetative and animal respiration promotes H₂CO₃ to high levels in the afternoon as photosynthesis removes CO₂ from water and can convert the bicarbonate ion HCO₃¯ to CO₂, CO₃^¯2, and water. The CO₂ is consumed in photosynthesis as the carbonate ion CO₃¯ reacts with water to release hydroxyl ions, increasing pH.

Directly related alkalinity quantifies the bicarbonate and carbonate contributions to pH as hardness measures calcium and magnesium ions, which react with water to form bicarbonate.

Alkalinity is measured by titration of a sample down to its equivalence point; the amount of acid consumed is equated to the total alkalinity ion buffering capacity of the sample, and is reported in terms of CaCO₃, like hardness. Divalent salts other than magnesium and calcium can contribute to hardness, and Cobb County usually assesses hardness per se, calculated from calcium and magnesium values reported when metals are run through the Inductively Coupled Plasma (ICP) process discussed later with metals. Alkalinity can, under some circumstances, be inferred from hardness. Remember, though, that sodium bicarbonate can contribute alkalinity not measured in hardness, as acidic, ground, or well water can have low or high hardness with no alkalinity.

Heavy Metal in Concert With Acidity. Many metals are assessed in Cobb County’s stream sampling program, including arsenic, cadmium, chromium, lead, mercury, and copper. Metals in aquatic systems are a result of weathering of soils and rocks, volcanoes, and human activities. Many metals, like iron, manganese, copper, and zinc, are in fact micronutrients. They are metabolically essential, but in excess are often poisonous. They enter organisms when the pH level in water falls, as this causes metal solubility to increase, because many metal ions are positive and precipitate out with hydroxide (OH-) at high pH levels. This explains why metals can be toxic in softer waters, as hardness discussed earlier maintains more alkaline buffer conditions, discouraging metal solubility. Streams in mining areas are usually acidic and have greater concentrations of dissolved metals, which discourage aquatic life. Benthic or bottom-dwelling organisms are most directly affected by metal in the sediment, because the repository of particulate materials in aquatic systems is the benthos.

The metal toxicity mechanism is complicated, and there are various models predicting toxicity of metals. For example, they can impinge upon the actions of ligands, which bind to target proteins. It should be easy to understand why metal ions interfere with these. Metals can also accumulate in different subcellular compartments (e.g., granules, cellular debris, and organelles) of aquatic organisms. To that point, “such subcellular partitioning is dynamic in response to metal exposure and other environmental conditions, and is metal- and organism-specific” (Wang and Rainbow 2006). The ionic form of a metal is often more toxic, because it can form toxic compounds with other ions and can cause cellular damage. In one experiment, lead was shown in fish to “inhibit Ca²⁺ influx after … exposure to Pb. There was also significant inhibition … of both Na⁺ and Cl⁻ uptake” (Rogers et al. 2003). Copper has also been shown to bind to active sites (within Cl⁻ cells) on macroinveretbrate gill membranes; it interacts with specific enzymes that regulate sodium and chloride ion levels and can cause death.

Chlorides in the form of ions (Cl⁻ ) comprise a major anion in water as well as in wastewater. They are assayed in the lab by forming mercuric chloride when chlorides liberate the thiocyanate ion from mercuric thiocyanate; the free thiocyanate ions in the presence of ferric iron form a colored ferric thiocyanate. Its intensity is proportional to the original chloride concentration.

Metal samples are collected in 125-milliliter plastic bottles and preserved with nitric acid before signing over to lab personnel. They are assessed by the ICP method, an analytical technique used for the detection of trace metals in environmental samples. Inductively coupled plasma is a very high temperature (7,000- to 8,000-K) excitation source plasma that desolvates, vaporizes, excites, and ionizes atoms. The primary goal of ICP is to get elements to emit characteristic wavelength specific light after ionization, which can be measured.

Biochemical Oxygen on Demand. Biochemical oxygen demand (BOD) and chemical oxygen demand (COD) are measures of microbiological respiration and organic biodegradation demand on dissolved oxygen, respectively. Bacteria feeding on a given mass of food source, such as sewage solids, generally extract oxygen from water on demand, unfortunately for those organisms stressed by lower DO. Organic compounds existing in waters potentially, and at different rates, can be oxidized by oxygen in the water that would otherwise support life.

To measure COD levels, samples are poured from the larger “general” bottle and preserved at a pH of less than 2. The COD test is based on the fact that almost all organic compounds can be oxidized to carbon dioxide with a strong oxidizing agent under acidic conditions. The COD sample is refluxed (liquid distillate is reintroduced by the distillation column) in a strong acid solution with a known excess of potassium dichromate, and, after digestion, the reduced dichromate/organic compound solution is assessed by spectrophotometry and its oxygen reducing equivalent is recorded. Because COD can determine the quantity of organic pollutants found in surface water, COD is a useful water-quality measure.

BOD samples are gathered in 300-milliliter glass bottles, and the oxygen consumed by microbial aerobes feeding on organic material in the sample is measured over five days. COD and BOD are expressed in milligrams per liter, which indicates the mass of oxygen consumed per liter of solution. BOD is particularly of concern where sewage or food industry discharges are introduced into freshwater, because such nutrients support microorganisms that can consume DO down to levels dangerous to aquatic life.

Total Suspended Solids. Turbidity can indicate general health of waters. It is caused by suspended and dissolved matter like clay and silt from soil erosion, organic material, plankton, organic acids, and anthropogenic source dyes. Turbidity levels can indicate degrees of poor land development practices and help gauge the effectiveness of stormwater management practices. Turbidity can increase water temperature, as suspended particles absorb sunlight heat; this drives critical DO out of solution and can upset temperature-sensitive metabolic balances. In addition, in turbid conditions, plants receive less sunlight, so there is less plant—and therefore oxygen—production. Turbidity can harm macroinvertebrates, fish, and their eggs, interfering with oxygen and nutrient diffusion across sensitive membranes. Curiously, turbid water dwellers like catfish stress in clearer waters, and their growth and survival are impacted.

Turbidity samples are drawn from a 2-liter “general” bottle, and turbidity is measured by a turbidimeter, which measures the scattering of light by the suspended material. The unit of measurement is known as a nephelometric turbidity unit.

Total suspended solids (TSS) are the solids in a sample that can be caught and then weighed on a filter and consist of larger, undissolved particles like pollen and coarse soil.

Related total dissolved solids (TDS) consist of all inorganic and organic substances in a molecular, ionized, or microgranular form.

Nutrients: Freshwater’s Overachievers. Cobb County stream-sampling personnel fill bottles and preserve them at a pH of less than 2 for nutrient sampling; the parameters tested are nitrate and nitrite, ammonia, total Kjeldahl nitrogen (TKN), and phosphorous. Aquatic biota depend on nutrients, as primary producing algae and phytoplankton mentioned earlier absorb nutrients as they fix carbon from CO₂ to carbohydrates and are consumed by higher life. However, streams and receiving freshwater ponds and lakes can suffer eutrophication, as nitrate- and phosphate-loaded fertilizers, detergents, and other pollutants lead to overabundant flora that consume oxygen at night and carbon dioxide in the day, upsetting DO and pH balances. Bacteria feeding on dying plants also consume DO through aerobic respiration. Surface algae prevent sunlight from reaching intermediate and deeper plant life. Indeed, when nutrients are too many, we get too little DO and too little balance in freshwater systems.

Ammonia per se in ponds and streams is usually a result of decomposed organic waste from decayed algae, plants, and animals, as well as metabolic waste of aquatic dwellers. It exists in the more toxic gas form NH₃ or as the ammonium ion NH₄₊. Ammonia can be removed by bacteria that convert it to nitrite, then to nitrate. The bacteria thrive at pH levels between 7 and 9, and between 75 and 85 degrees Fahrenheit. Nitrite is toxic to fish, but nitrate is tolerated to appreciable levels.

Nitrate and unstable nitrite are common in aquatic systems. Nitrogen (and nitrate) is essential for protein synthesis in plants and animals.

Phosphorus is key to the phosphate component in ATP (the biological molecule adenosine triphosphate) and is also in DNA; it is essential to plant growth, and yet it controls growth as it occurs limitedly in nature. Human waste and fertilizers can tip the balance and introduce more phosphorus into a system, causing gratuitous plant blooms, discussed earlier.

TKN is ammonia nitrogen and organic nitrogen; ammonia makes up the greatest fraction of TKN. A high TKN level can indicate domestic sewage, farm runoff, or ammonia fertilizers. Nutrients are analyzed by flow injection analysis.

Separation by Oiling Point. Surfactants usually enter waters from industrial and domestic laundering and cleaning operations. Surfactants like methylene blue activating substances (MBAS) are common and are specifically tested for; they have a long-carbon-chain hydrophobic end and a hydrophilic end with, for example, the sodium ion. “Such molecules tend to congregate at the interfaces between the aqueous medium and the other phases of the system such as air, oily liquids, and particles, thus imparting properties such as foaming, emulsification, and particle suspension” (Clesceri et al. 1998). This occurs because, generally, more energy is required to maintain the hydrophobic or “water-hating” chains suspended in water than to line them up at interfaces with the hydrophilic or water-loving polar “heads” in the water phase and the carbon chains in the other medium. Surface tension is compromised by surfactants as the tight, energy-saving smaller surface area of water that is sacrificed in order to accommodate a surface layer of interphase (water/air) surfactant molecules, and for the reason just described.

In the lab, Cobb County personnel test for the anionic surfactant MBAS that is present in many detergents. Anionic MBAS brings cationic methylene blue out of aqueous solution into an immiscible organic liquid substance as the two pair opposite charges. The resulting blue color is then assessed. Its relative intensity is directly related to the original MBAS present in the bath of excess methylene blue (Clesceri et al. 1998).

Bad Bug. During chemical sampling, Cobb County stream personnel also grab a “fecal bag” sample and ice it for analysis of coliform-forming units formed after 24 hours in a lactose medium. The presence in numbers of the fecal coliform group indicate the probable presence of group members like Escherichia Coli, and possibly the E. Coli member 0157:H 57, which can cause severe distress and death in the infirm, as its shiga toxin halts protein synthesis in target cells.

Everyone Lives Downstream
As I drafted this article, I agonized a little over just how to articulate urbanized watershed chemical stream monitoring’s reaching significance for the citizens who recreate in and drink water they must take for granted. I could not find, and cannot attempt to present, anything more straightforward than the US Geological Survey’s poster publication Everyone Lives Downstream. Its convincing, condensed insert discussions and graphics range from waterborne pathogens to sewage overflows to phosphorus, urban runoff, population growth, erosion and sedimentation, pesticides, and toxic metals as they relate to regional water quality. The following narrative succinctly articulating water-quality issues for metro Atlanta and other developing regions frames the top of the publication:

Rapid growth in Metropolitan Atlanta is transforming the headwaters of many watersheds in Georgia from forests and pastures to suburban and urban land … The growth of Metropolitan Atlanta has had a wide range of effects on the water resources in the upper Chattahoochee River watershed … The continuing spread of the metropolitan area has begun a cycle of land disturbance with associated erosion and sedimentation that last occurred during periods of widespread logging, cotton cultivation, and hydraulic mining in the area. Increased storm runoff from roofs, roads, driveways, and parking lots has a wide range of effects on the upper Chattahoochee River and tributaries that supply drinking water.

Municipalities are spending large amounts of money to expand and upgrade sewer systems, sewage-treatment facilities, and systems that supply drinking water to meet the demands of the growing population and the more stringent Federal and State environmental regulations. However, as water quality from point sources in the metropolitan area improves, assessments indicate the growing importance of nonpoint sources of contaminants in and downstream of the metropolitan area. State monitoring programs show widespread impairment of streams in the metropolitan area, primarily from bacteria and toxic metals present in urban runoff. A water-quality assessment of the Chattahoochee watershed conducted by the US Geological Survey shows numerous pesticides are present in streams within the metropolitan area. Traces of toxic chemicals, though now banned from use, persist in area streams and fish, and thus, pose a continued threat to aquatic and human health.

The long-term challenge for managing the water resources in the upper Chattahoochee River watershed is to minimize nonpoint-source contamination in the Atlanta Metropolitan area (USGS).

The inserts condense education “mind bytes”: “Many sewer lines are constructed adjacent to streams to take advantage of the continuous gradual slopes of stream valleys. Blockages, inadequate carrying capacity, leaking pipes and power outages at pumping stations, often lead to sewage overflows into nearby streams.”

In strategy, the publication offers watershed protection through such measures as planning and zoning, establishment of buffer zones, controlled building density, and other means; public education programs; and Adopt-A-Stream programs to train local volunteers to evaluate and protect water resources.

Indisputably, for those who regulate municipal source water, for those who play in and drink it, or for those who just drive over it, the time indeed has come to speak of many things.