Applied Wetlands Science - Chapter 12 ppt

KentCONTENTS Managing WatershedsElements of Management Definition and DelineationWatershed CharacterizationPrioritization Developing and Implementing a Watershed ProgramMonitor and Adjust

Kent, Donald M “Watershed Management”

Applied Wetlands Science and Technology

Editor Donald M Kent

Boca Raton: CRC Press LLC,2001

CHAPTER 12 Watershed ManagementDonald M Kent

CONTENTS

Managing WatershedsElements of Management

Definition and DelineationWatershed CharacterizationPrioritization

Developing and Implementing a Watershed ProgramMonitor and Adjust

Source ControlMunicipal WastewaterBest Management Practices (BMPs)

Agricultural BMPsUrban Stormwater Runoff BMPsInnovative Solutions

Watershed-Based TradingCase Study—the Chesapeake Bay WatershedAnacostia Watershed RestorationReferences

Wetlands tend to occupy topographic low points in the landscape and are thusrecipient of water and eroded materials from higher in the landscape The influx ofwater and other materials gives each wetland its character, supports its internalprocesses, and in part determines wetland function and value In meager or excessamounts, water and other materials may alter or hinder wetland processes and

diminish functions and values Therefore, effective wetland management requiresmanagement of parts of the landscape contributing water and other materials towetlands The contributing areas of the landscape constitute the watershed.The concept of managing at the scale of watersheds has been evolving in theUnited States for about 100 years In the 1890s, the U.S Inland Waterways Com-mission recommended to Congress that each river system be treated as an integratedsystem Throughout the first half of the 20th century, the focus of watershed man-agement was on the use of water resources for energy, navigation, flood control,irrigation, and drinking water (U.S Environmental Protection Agency, 1995b) In

1944, the Pick-Sloan Plan proposed to reduce flood damage by constructing largedams The plan was opposed by some that believed that more effective flood controlcould be accomplished by managing rural, upstream watersheds than by constructinglarge dams (Peterson, 1998)

During the 1950s and 1960s the management emphasis shifted to protectingdrinking water (U.S Environmental Protection Agency, 1995b) The Federal WaterPollution Control Act of 1956 funded publicly owned treatment works, and the WaterQuality Act of 1965 required states to develop standards for interstate waters.The Clean Water Act and Safe Drinking Water Act of the 1970s and 1980s furtheremphasized large-scale protection of water resources The Clean Water Act estab-lished a permitting program for point source polluters, provided additional fundingfor wastewater treatment and state water quality programs, and authorized programs

to reduce, prevent, and eliminate pollution to surface and ground waters The SafeDrinking Water Act established the basis for protecting surface and ground watersupplies with an emphasis on preventing contamination

In recent years, the focus of water quality management has shifted to includenonpoint sources of pollution Watershed management provides a necessary frame-work for managing nonpoint pollution As a result, the U.S Environmental Protec-tion Agency developed the Watershed Protection Approach (1995a) Through focus

on hydrologically defined resource areas, rather than jurisdictional boundaries, theWatershed Protection Approach is designed to more effectively protect and restoreaquatic resources and protect human health than the historical approaches TheApproach targets priority problems, involves stakeholders, seeks integrated solu-tions, and measures success

MANAGING WATERSHEDS

A watershed is technically a divide separating one drainage area from another(Chow, 1964) More commonly, and as applied to watershed management, water-sheds are areas that drain to surface water bodies Watersheds come in all shapes,and range in size from a few to several million km2 Depending upon the type andextent of water quality problems, administrative boundaries, and technical con-straints, watershed management may be applied to local watersheds, major water-sheds, river basins, aquifers, or composites of surface watersheds and aquifers.From a water quality standpoint, watersheds have two elements Terrestrialhabitats, including urban, suburban, and rural areas, are the sources of particulate

and dissolved materials Particulate and dissolved materials derive from wastewaterdischarges, stormwater runoff, and erosion The other element, surface water bodiesincluding streams, rivers, ponds, lakes, estuaries, and coastal habitats, are the recep-tacles for particulate and dissolved materials Materials may become trapped in thereceiving water body or be transported downstream.

Watershed management attempts to sustain and improve water quality by ing on hydrologically defined resource areas This is in contrast to historical efforts

focus-to regulate individual point sources of pollution Watershed management also grates various efforts to manage nonpoint sources of pollution A fundamentalpremise of watershed management is that water quality and ecosystem issues can

inte-be more effectively addressed at the watershed level than at the level of the individualwaterbody or polluter (U.S Environmental Protection Agency, 1995a) Becausewatershed management addresses both point and nonpoint sources of pollution, it

is an effective mechanism for protecting water and habitat quality

Several benefits, all of which save time and money, derive from watershedmanagement’s holistic approach (U.S Environmental Protection Agency, 1995a, b,1996a) Regulatory efficiency is enhanced by coordinated monitoring, shared respon-sibility for assessment, and consolidated permitting Decision making is improved

by consideration of all stressors affecting water quality, systematic review of shed basins, an increase in the availability and level of detail of watershed informa-tion, and a pooling of resources An enlarged information base, systematic review,and enhanced coordination improve targeting of resources; and resources are focused

water-on envirwater-onmental results rather than programmatic activities such as permitting andreporting Finally, innovative solutions are encouraged by watershed management,including ecological restoration, protection of critical areas, wetland mitigationbanking, and watershed-based trading

Inherent to a successful watershed management program is stakeholder ment Stakeholders are individuals and organizations that are affected by waterquality management decisions This includes state and federal agencies charged withprotecting water quality, businesses that rely on water or discharge waste, andcitizens that use waterbodies and waterways for drinking water or recreation Stake-holders share responsibility for monitoring, setting priorities, and developing andimplementing management strategies

involve-Elements of Management

Watershed management has five elements (see Figure 1):

1 Definition and delineation

2 Characterization

3 Prioritization

4 Program development and implementation

5 Monitoring and adjustmentEach of these elements will now be discussed briefly

In addition, watershed management requires development of a project team andpublic support The former may include local, state, regional, and federal regulatingagencies, research scientists, policymakers, trade associations representative ofpollution sources, and nongovernmental organizations The composition of theproject team will vary with geographic scope and institutional infrastructure Publicsupport is important for developing applicable management goals, encouraging

Figure 1 Elements of a watershed management program.

cooperation among disparate project team members, implementing managementactions, and monitoring success.

Definition and Delineation

Definition and delineation are the selection of management boundaries agement boundaries may encompass local watersheds, groups of local watersheds,river basins, aquifers, or some combination of watersheds, basins, and aquifers.Ideally, management boundaries should be large enough to benefit from an economy

Man-of scale, take advantage Man-of government and technical expertise, and yet be able for the long term (U.S Environmental Protection Agency, 1995a) As mentionedabove, the boundary will in practice reflect the type and extent of the water qualityissues and administrative boundaries Nested watersheds, where small watershedsare subsets of larger watersheds, facilitate management at multiple scales (U.S.Environmental Protection Agency, 1995b) For example, local stakeholders canmanage local watersheds, while state or regional entities can manage river basins

manage-Watershed Characterization

The watershed should be characterized after the management boundary has beendefined and delineated The purpose of characterization is to describe the physicalcharacteristics of the watershed, to determine the water quality status and trends ofwatershed waters, and to identify potential water quality stressors and their sources.The physical description of the watershed should include geology, topography,soils, land use, hydrology, and significant biological resources The latter mayinclude threatened and endangered species and critical habitat Surface water bodiesshould be described with respect to their designated uses and physicochemical andbiological water quality A baseline water quality monitoring program will need to

be established if existing information is inadequate Ideally, the baseline programwill include physical, chemical, and biological indicators of water condition (seeChapter 8)

Potential point (e.g., wastewater treatment facilities, industrial discharges) andnonpoint (e.g., urban stormwater, agricultural runoff) sources of pollution should bedescribed by location, type, and absolute and relative loadings to the receiving body(Table 1) Rarely does one source or one type of pollution cause a problem Existingcontrol measures should also be described Projecting expected watershed demo-graphics and land use as they relate to potential sources of pollutants is also helpful

at this stage

Prioritization

Watershed characterization may identify few issues, and available resourcesmay be sufficient to effect comprehensive management More likely, the extent anddegree of watershed issues will exceed the resources expected to be available formanagement In such instances, watershed goals, targets, and action items must beprioritized Prioritization may be logically directed at individual waterbodies or

waterways within the watershed (Table 2) Alternatively, specific pollutants or lutant sources could be prioritized

pol-Water quality impairments that pose a risk to public health should receive toppriority and be addressed as quickly as possible Other policy-related criteria includewater quality goals, designated water uses, and waterbody or waterway value Thesecriteria are related when the waterbody or waterway is used for drinking water,commercial fishing, or recreation Waters with more stringent water quality goals,greater designated uses, and higher value might reasonably receive high priority

Table 1 Water Quality Stressors Typically Associated with Land

Uses and Land Use Activities Land Use or Activity Stressor

Agriculture Sediment

Nutrients Bacteria Pesticides Construction Sediment Forestry Sediment Golf courses Nutrients

Pesticides Impoundments Altered hydrology Industrial discharge Inorganic and organic chemicals

Metals Mining Sediments

Metals Septic systems Nutrients

Bacteria Urban runoff Sediment

Nutrients Bacteria Pesticides Altered hydrology Metals

Wastewater treatment facility Nutrients

Bacteria

Table 2 Criteria for Prioritizing Watershed

Management Efforts Directed at Improving Waterbody and Waterway Water Quality

Degree of waterbody/waterway impairment Designated use of the waterbody/waterway Knowledge about water quality, stressors, and sources Probability of success

Resources available for management Risk to ecosystem health

Risk to public health Stakeholder support Type of waterbody/waterway impairment Value of the waterbody/waterway Water quality goals for the waterbody/waterway

Programmatic criteria, including knowledge about watershed waters, resourcesavailable for management, stakeholder support, and probability of success, alsoimpact the implementation of management actions Insufficient knowledge aboutthe watershed will require a return to the characterization stage Alternatively,insufficient knowledge about individual waters may eliminate their considerationfrom the management process In the absence of sufficient resources, some goals,targets, and action items may have to be eliminated Lack of stakeholder supportmay necessitate initiation of an education program and postponement of actions.Conversely, projects with stakeholder support will be easier to implement Goals,targets, and action items with a high probability of success are important at thebeginning of a watershed management program to demonstrate program effective-ness to stakeholders.

The type and degree of water quality impairment and ecosystem health relatedirectly to the physical, chemical, and biological character of the waterbody orwaterway Waterbody and waterway water quality can be compared against regula-tory or designated use standards or against the minimum requirements of aquaticorganisms such as fish Reviewing plant and animal richness and diversity can assessecosystem health Systems with impaired water quality or poor ecosystem healthmay be priorities

As noted above, the threat to public health will be the superceding criteria forprioritization In the absence of a public health risk, other criteria may becomesuperceding based upon local or regional policy concerns, programmatic constraints,

or stakeholder interest Nevertheless, particularly in the early stages of a watershedmanagement program, formalized evaluation of assorted criteria facilitates consid-eration of multiple perspectives, flexible problem solving, and stakeholder support.This approach also provides a basis for reevaluating a goal, target, or action item ifcircumstances change A matrix analogous to the site selection criteria matrix illus-trated in Chapter 5 could be used to ensure careful consideration of all issues

Developing and Implementing a Watershed Program

Developing and implementing a watershed management program requiresknowledge of the type and degree of water quality problems, the source of theproblems, and the available and achievable solutions This was achieved in thecharacterization stage The prioritization stage helped determine the sequence ofmanagement actions This stage has two components: program development andprogram implementation

Program development focuses on defining a strategy for improving watershedwater quality This is accomplished by setting management goals, targets, and actionitems Goals are long-term visions of the watershed and may be programmatic,activity-based, centered on best management practices (BMPs) installation, waterquality-oriented, or biological An example goal might be stating that all surfacewaters will support commercial and recreational fisheries by the year 2010 Setting

of additional near-term or interim goals may facilitate continued stakeholder supportand a sense that progress is being made toward long-term goals Goals are supported

by targets, which are specific, quantifiable objectives For example, reducing nutrient

loads by 50 percent and restoring historical riparian vegetation will restore cial and recreational fisheries Finally, action items ensure that goals and targets will

commer-be achieved Action items are specific projects with assigned roles and ities and a scheduled completion date For example, the local chapter of the ecolog-ical restoration society will restore bank vegetation along a 1 km stretch of theheadwater stream extending from point A to point B, beginning May 1, 2000 andcompleting the restoration by June 30, 2000

responsibil-Together, the goals, targets, and action items will be a mix of local and wide regulations, management practices, economic incentives, and education andtraining programs Again, one of the benefits of watershed management is theopportunity for innovative solutions, such as pollution trading (discussed later inthis chapter), ecological restoration (see Chapter 6), and mitigation banking (seeChapter 7) Installation of controls should be site specific and tailored to hydrology,topography, geology, the resource to be protected, and politics

watershed-Documentation in the form of a watershed management plan is fundamental toprogram development The plan should describe the watershed, characterize waterquality and pollutant sources, list priorities, and describe the process leading tosetting of goals, targets, and action items In addition, the plan should define rolesand responsibilities, identify funding sources and mechanisms, establish a schedule,and describe how program effectiveness will be assessed Documenting development

of the watershed management program facilitates reevaluation, clarifies intent andthe decision-making process, and serves as a reference for future management Theplan should be periodically updated

Program implementation requires reaching consensus on goals, targets, andaction items, developing an organizational infrastructure for effecting controls, andestablishing procedures Consensus is facilitated by stakeholder involvement inwatershed definition and delineation, characterization, prioritization, and programdevelopment An organizational infrastructure must carry out management actions,account for funds, maintain the schedule, and communicate to stakeholders Controlsmust be properly installed and subject to periodic inspection and maintenance.Effective actions should be documented as procedures and become part of thewatershed plan

Successful watershed management programs will secure commitments for ing and installation and management of controls Commitments should come fromboth those implementing and administering actions and from those installing con-trols Commitments may be formal or rely on public accountability (U.S Environ-mental Protection Agency, 1995a) The former are written and detail expectationsfor all parties The latter provide for public review through meetings or publications.Funding may derive from the operating budgets of participating organizations,businesses, municipal bonds, taxes, grants from nonparticipating organizations, dona-tions, or fees Additional support may come from in-kind contributions Large orcomplex watershed management programs may benefit from a funding schedule Theschedule would reflect potential funding sources, application dates, dates funding isrequired, and tasks to obtain funding (U.S Environmental Protection Agency, 1995a).Ultimately, successful programs have multiple incentives for stakeholder partic-ipation (Table 3, U.S Environmental Protection Agency, 1995a) Stakeholders

fund-should be thoroughly educated about the reasons, goals, and progress of the shed management program Individuals responsible for implementing, installing,and maintaining pollution controls should receive adequate training and technicalassistance Individuals and businesses should be compensated for control costs thatbenefit society as a whole.

water-Monitor and Adjust

Ideally, monitoring will have been effected prior to the implementation of anymanagement actions to characterize the watershed and provide a baseline for com-parison, and after the implementation of management actions, monitoring documentsthe effectiveness, or ineffectiveness, of the watershed management program Docu-mented monitoring results also provide the basis for communicating with stakehold-ers and facilitate long-term maintenance of pollutant controls

Perhaps most importantly, monitoring provides a basis for making adjustments

to the watershed management program Adjustments will be necessary if ment actions are partly or wholly ineffective at achieving program goals or targets.Program adjustments will also be necessary if management actions are effective;goals and targets must be reprioritized Finally, monitoring provides a basis formaking program adjustments in response to significant land-use changes

manage-Monitoring plans should derive directly from program goals, targets, and actionitems Continuing with the earlier example, monitoring of native fisheries mightinclude direct counts of fish, preferably by age class Depending upon programgoals, monitoring may encompass biological, chemical, physical, and program-matic parameters (see Chapter 8) Table 4 lists parameters commonly monitored

as part of a watershed management program Chemical and physical parametersshould be monitored routinely, as well as during storm events, to characterize theinitial flush of pollutants Biological parameters effectively may be monitoredseasonally or annually

Voluntary citizen monitoring programs have become increasingly common inthe United States The success of these programs is dependent upon effective trainingand a good quality assurance/quality control program

Table 3 Incentives for Participating in a Watershed Management Program

(U.S Environmental Protection Agency, 1995a)

Cost–Share Payment to polluters for the installation of controls

Education Including function and value of waterbodies and waterways; goals,

targets, and action items; benefits of controls; and progress Purchase Purchase of critical areas including source water protection areas,

riparian areas, critical habitat, lands from owners unwilling to institute controls

Regulation Environmental laws and regulations, zoning ordinances, use

restrictions, performance standards Tax advantage Conservation easements, credits for installation of controls Technical assistance Installation of controls, training of on-site managers, provision of

procedural documents

SOURCE CONTROL Municipal Wastewater

Municipal wastewater contains suspended solids, biodegradable organics (e.g.,proteins, carbohydrates, fats), pathogens, and nutrients such as nitrogen and phos-phorus Depending upon the service area, wastewater may also contain organic andinorganic carcinogens, mutagens, teratogens, acutely toxic compounds, pesticides,heavy metals, and dissolved organics In the absence of high concentrations of thelatter constituents, nutrients are the primary constituents of concern Excessivenutrients discharged to aquatic environments increase the growth of undesirableplants and algae, decrease dissolved oxygen levels, and in some instances promoteammonia toxicity

In the early 20th century in the United States, wastewater was discharged directly

to streams and rivers via storm sewers The accumulation of sludge, odors, and otherunsightly conditions led to the separation of storm drains and sewers, and theconstruction of wastewater treatment facilities Initially, most treatment facilitiesprovided only primary treatment, which consisted of screening and sedimentation

to remove floating and settleable solids Later, the U.S Environmental ProtectionAgency mandated secondary treatment as the minimum standard for facilities Sec-ondary treatment involves biological and chemical processes to remove most of theorganic matter

Treated wastewater was historically disposed of by the easiest method possible.For coastal communities, this may have included ocean discharge, a practice that is

Table 4 Parameters Likely To Be Monitored in a

Watershed Management Program Type Parameter

Biological Benthic macroinvertebrate richness

Biotic index Fish and wildlife abundance Fish and wildlife richness Vegetation cover or density Vegetation richness Chemical Biological oxygen demand

Dissolved oxygen Nutrient concentration pH

Toxicants Physical Suspended solids

Temperature Turbidity Programmatic Enforcement actions

Funds received and disbursed Meetings

Permit issuance Reports

increasingly discouraged (Metcalf and Eddy, 1991) Away from the coast, discharge

to inland surface waters is the most common method for disposing of treatedwastewater Surface discharge relies on the assimilative capacity of the receivingwater, a capacity that has been increasingly exceeded for many waterways in thelatter part of the 20th century In response, many wastewater facilities are beingrequired to provide advanced treatment

Advanced wastewater treatment removes additional suspended and dissolvedsubstances, especially nitrogen and phosphorus At conventional treatment facilities,advanced processes remove nitrogen by biological nitrification and denitrification,separate stage biological denitrification, airstripping, breakpoint chlorination, andion exchange (Metcalf and Eddy, 1991) Phosphorus is removed by chemical pre-cipitation with metal salts or lime, and filtration Microorganisms can also be stressed

to force additional phosphorus uptake

Large wastewater facilities exceed the treatment needs and financial resources

of small communities Clustered homes may use a package treatment facility Moretypically, rural homes will use on-site treatment consisting of a septic tank anddisposal field BOD, SS, N, P, bacteria, and viruses are the primary constituents ofconcern with on-site disposal Onsite systems should be set back from surface andground waters, the distance of the setback contingent upon system capacity and soilpermeability (Metcalf and Eddy, 1991) Schueler (1995) has noted that more thanone on-site septic system per 2.8 ha can result in shellfish bed closures (Figure 2)

Figure 2 On-site septic systems located too close to coastal waters can result in shellfish

bed closures.

Natural treatment systems have many of the same treatment processes as ventional facilities (e.g., sedimentation, filtration) and have additional, unique treat-ment processes (e.g., photosynthesis, plant uptake) Land-based and wetland systemseffect treatment of municipal wastewater Both types of systems are preceded bymechanical pretreatment including fine screening and primary sedimentation.The three fundamental types of land treatment are slow rate, rapid infiltration,and overland flow (Metcalf and Eddy, 1991) Slow rate systems are potentially themost effective land treatment and entail the application of wastewater to vegetatedland to provide treatment and irrigation Wastewater is consumed by plants and isevapotranspirated Treatment is effected in large part by wastewater percolationthrough the soil Rapid infiltration systems entail the intermittent application ofwastewater to shallow, unvegetated infiltration or spreading basins As with slowrate systems, treatment occurs as wastewater percolates through the soil Overlandflow systems are relatively less effective than slow rate and rapid infiltration systemsand are used in areas with relatively impermeable soils Wastewater is distributedacross the upper part of a graded, vegetated slope, and runoff is collected in ditches

con-at the toe of the slope Trecon-atment is effected primarily by evapotranspircon-ation.Wetland systems are inundated areas supporting aquatic vegetation (Kadlec andKnight, 1996) Filtration, sedimentation, precipitation, plant uptake, and other pro-cesses effect significant reduction and removal of wastewater constituents Chapter 9discusses wetland treatment systems at length

Best Management Practices (BMPs)

Best management practices (BMPs) are operational procedures designed toreduce pollutant discharge to surface water or groundwater and to minimize changes

to hydrology and hydraulics BMPs reduce the pollutant load by reducing the volume

of discharge water, reducing the concentration of pollutants in discharged water, orboth A watershed management program may include agricultural and urban BMPs(Tables 5 and 6)

Agricultural BMPs

Modern agricultural practices rely on fertilizers and pesticides to increase cropyield Excess or misapplied fertilizer can cause algal blooms, stimulate growth ofnoxious plants, and decrease available oxygen for fish and other aquatic organisms.High concentrations of nitrogen may cause methemoglobinemia (see Chapter 5).Pesticides can be chronically or acutely toxic to humans and aquatic organisms.Agricultural practices may also be accompanied by excessive erosion Sedimenterosion increases surface water turbidity and may smother benthic organisms Nutri-ents, pesticides, and heavy metals occur in particulate form or can be attached todirt, sediment, and detritus Sediment accumulation may also alter waterway hydrol-ogy and hydraulics by increasing flow velocity and decreasing flow capacity.Fertilizer BMPs operate by reducing the amount of fertilizer used and retainingunused fertilizer on-site (Bottcher et al., 1995; South Florida Water ManagementDistrict, 1999) BMPs include soil chemistry management and calibrated soil