Nutrient Management Strategy - Government of Manitoba

Information Bulletin2000 - 02EManitobaConservationApril 20, 2000Development of a Nutrient ManagementStrategy for Surface Waters in SouthernManitobaForewordOne of the greatest challenges facing water quality managers in the prairie and southern portionof the boreal forest regions of Canada and the northern United States is to better understand and tocontrol, where necessary, the introduction of plant nutrients into surface waters. Prairie soils tend to benaturally rich in nitrogen and phosphorus, streams may be turbid thus limiting light penetration, andphosphorus - the nutrient most easily controlled from point-source discharges - may not be the factor thatlimits algal growth in many prairie water bodies. Eutrophication of surface waters is a scientificallycomplex process and nutrient management options can be difficult and costly to implement.The purpose of this draft document is to outline the main tasks and issues that need to beconsidered and addressed as a nutrient management strategy is developed and implemented. Yourcomments and suggestions on the attached draft are welcomed as we proceed to develop and toimplement a nutrient management strategy.Please forward comments on the attached draft by June 30, 2000 to the following:Dwight Williamson, ManagerWater Quality Management SectionManitoba Conservation123 Main Street, Suite 160Winnipeg MB R3C 1A5Telephone: (204) 945-7030Toll Free: 1-800-282-8069 (7030)Facsimile: (204) 948-2357E-mail: dwilliamso@gov.mb.caPlease feel free to contact Dwight Williamson should you require further information.For Additional Information, Visit Manitoba Conservation’s Website for Current Issues - Latest Newswww.gov.mb.ca/environ/

Page 1IntroductionEutrophication is one of the most importantwater quality issues in the prairie and boreal plainecozones in western Canada. Water qualitymonitoring results indicate that most of the largeriver systems that flow across the prairie andboreal plain ecozones contain relatively highconcentrations of phosphorus and nitrogen, thetwo nutrients most commonly associated witheutrophication. The main factors that maycontribute to the high nutrient content in thesesystems include erosion of naturally fertile soils,surface run-off of fertilizers from cultivated fields,run-off from livestock pasture and feedlots, urbanrun-off and storm sewer discharges, andagricultural, industrial, and urban sewage effluentdischarges. Some of the larger river systems thatare of particular concern to southern Manitobainclude the Assiniboine, Souris, and Red Riversystems, all of which carry significant amounts ofnutrients into the province from the west andsouth.Concerns have been raised over the potentialfor eutrophication processes to not only negativelyimpact rivers and streams that flow through theregion, but also adversely affect the water qualityof Lake Winnipeg, since the lake is the eventualrecipient of the nutrient load transported by manyof these rivers and streams.growth of opportunistic species, resulting in anoverall decrease in biological diversity across theentire ecosystem. As well, the decay process thatfollows the decline or die-off of algal andmacrophyte populations uses up large amounts ofdissolved oxygen. This can have seriousconsequences on aquatic animals, such as fish andinvertebrates, which rely on an adequate supply ofdissolved oxygen for survival. Low oxygenconcentrations also result in the release of thenutrient phosphorus from the sediment, making itavailable for algal growth. Eutrophication mayalso decrease the suitability of a water supply fordomestic use (including human drinking),livestock watering, and recreational use. Algalblooms associated with eutrophic waters are oftendominated by species of blue-green algae, some ofwhich are known producers of potent nerve andliver toxins. Such a situation can present a healthrisk for humans, household pets, and livestock thatdrink the water, and for people who use the waterfor recreational purposes. There is also someevidence that the toxins produced by blue-greensmay be transferred up the food web, and mayadversely affect wildlife populations such as fishand water birds. Besides being potentially toxic,the presence of an algal bloom in a drinking watersource can clog treatment plant filters, and oftenimparts an unsightly appearance, and unpleasanttaste and odour to the finished water. Algalblooms and extensive macrophyte growth are alsoconsidered aesthetically unappealing and candetract from the recreational use of a surfacewater.The water quality problems that arise as aresult of eutrophication of drinking andrecreational waters are difficult and expensive toremedy. For drinking water sources the cost ofadditional treatment may be prohibitive in manyjurisdictions, while for recreational waterbodies, adecline in the aesthetic quality of the water canadversely affect tourism, and lead to decreasedland and cottage values.Nutrient enrichment can directly or indirectlyimpact the water quality of surface waters. Anoverabundance of nutrients can lead to excessivegrowth of algae and macrophytes within anaquatic system, which can greatly alter the overallstructure of the ecosystem by favouring theNutrient enrichment has long been recognizedas a major water quality issue. Many importantsteps have been implemented in Manitoba andelsewhere to better understand and to implementappropriate and feasible control options. Waterquality objectives were first developed forFor Additional Information, Visit Manitoba Conservation’s Website for Current Issues - Latest Newswww.gov.mb.ca/environ/

Page 2phosphorus in the mid-1970s in many jurisdictionsin North America, but were largely focussed onpreventing eutrophication of lakes. Theseapproaches have been used in a number of cases inManitoba, particularly for bodies of water knownto be sensitive to nutrient addition. For example,in several cases municipal and agriculturaleffluents are used for irrigation purposes on eithergrowing crops or parklands as an alternative todirect discharge to streams or rivers, someeffluents are discharged to wetlands or constructedwetlands, and phosphorus-removal technologiesare used in at least one other case. Adoption ofthe recent Livestock Manure and MortalityManagement Regulation requires the applicationof manure as a fertilizer at agronomic rates. Inaddition, many local stewardship groups andConservation Districts are promoting therestoration of wetlands and protective riparianzones as a means of both preserving habitat andintercepting runoff from agricultural lands.However, despite these efforts in Manitobaand similar efforts elsewhere, eutrophicationremains an important water quality issue. This hasprompted many agencies to begin to develop newnutrient management strategies or approachesaimed at controlling excessive inputs of nutrientsto surface waters. The Water QualityManagement Section of Manitoba Conservationhas responded to the nutrient enrichment issue byidentifying the need for the development of along-term nutrient management strategy for theprovince and to begin work towards this strategy.The purpose of this document is to identify themain challenges, tasks, and issues that will have tobe considered in the development of a nutrientmanagement strategy for waterways in southernManitoba. The Water Quality ManagementSection has already begun to address many of theitems outlined below, and will continue to buildonand refine these subject areas as more waterquality data is collected and as information fromsimilar work being carried out in otherjurisdictions becomes available.Item 1 – Eutrophication in Southern ManitobaAn important first task in the development ofa nutrient management strategy for southernManitoba is to gather background information onthe current nutrient status of waterways in theregion. This task will require the followingactivities:A. Review and compare existing water qualityguidelines/objectives/criteria for nutrientrelated variables (phosphorus, nitrogen,chlorophyll-a, and turbidity) in Manitoba andelsewhere.B. Conduct a search of the Water QualityManagement Section database for data on thenutrient related variables phosphorus(including total, dissolved, and orthophosphorus),nitrogen (including ammonia,nitrate-nitrite, and total Kjeldahl nitrogen),chlorophyll-a, and turbidity in samplescollected from water quality monitoringstations in rivers and streams in Manitoba.C. Extract, summarize and interpret the data todetermine levels of exceedence above existingobjectives and to identify any spatial andtemporal trends in the data. It is important tounderstand whether key nutrients are changingwith time.D. Identify gaps in the existing database.1. Identify any nutrient related variables thatmay be useful in describing the nutrientstatus and degree of eutrophication within ariver or stream and that are currentlylacking or insufficiently represented in thedatabase.2. Develop a sampling plan to remedy datagaps. This involves creating a list of corevariables for analysis and prioritizingwhich stations to sample and where to addnew stations if required.For Additional Information, Visit Manitoba Conservation’s Website for Current Issues - Latest Newswww.gov.mb.ca/environ/

Page 3Item 2 - Derive Numeric Objectives for NutrientVariablesResults from preliminary work on some of theissues in Item 1 indicate that the current ManitobaSurface Water Quality Objectives and objectivesin place elsewhere in the prairies for nutrients areinadequate. Because of this, the derivation of newnumeric objectives for nutrient variables is one ofthe first challenges in the development of anutrient management strategy for southernManitoba. Numeric objectives, as opposed tonarrative objectives, are important in controllingeutrophication because they allow water qualitymanagers to make informed, scientificallydefensible decisions with regard to regulatingnutrient inputs to surface waters.Two approaches to deriving numeric nutrientobjectives will be used simultaneously. These are:(1) Regional Based Objectives and (2) ObjectivesBased on Receiving Waters.(1) Regional Based ObjectivesThe chemical and physical characteristics of awaterway are determined in large part by thefeatures of its drainage basin or watershed.Topography, natural vegetation cover, land-usepractices, climate, geology, and soil type can varyconsiderably between watersheds, and as a result,no two waterways are exactly the same in terms offlow regime, physical characteristics, and waterchemistry. The growth of algae and macrophytesis dependent in large part on the availability ofphosphorus and nitrogen. However, primaryproductivity in streams is also influenced by lightexposure, temperature, water clarity, flow regime,grazing, the presence of toxic pollutants, andmicro-nutrient concentrations, all of which varybetween waterways.Given the considerable variation that existsbetween aquatic systems, it is unrealistic that asingle numeric objective for each nutrient variablecould be applicable to all the rivers and streams insouthern Manitoba. It is apparent that more sitespecificobjectives are required. Although theestablishment of nutrient objectives for individualwaterways is impractical at this time, it isreasonable to consider deriving nutrient objectivesat a regional scale.Regional boundaries for regionally-basednutrient objectives can be based on ecologicalunits such as ecozones or ecoregions, or ondrainage units such as drainage basins orwatersheds. The scale at which the regionalboundaries are set is dependent on the level ofenvironmental variability that is deemedacceptable, and the amount of the resources thatcan be devoted to the derivation process.Once regional boundaries are established theprocess of developing nutrient objectives for theregions can proceed. Major tasks to undertake inthe development of regional nutrient objectivesinclude:A. Identify the major problems associated witheutrophication within each region andprioritize which regions and waterwaysrequire the most immediate attention.B. Identify core variables used to assesseutrophication in southern Manitoba (these arethe variables for which objectives will beestablished).C. Develop focused monitoring programs orstudies, if required, to better define therelationship between nutrients and primaryproductivity and to identify any temporal orspatial trends in rivers within each region.D. Identify reference streams or reaches thatrepresent ambient of non-impacted conditionswithin each region.E. Analyze the data using acceptable statisticalmethods and empirical and simulation modelsto identify relationships between nutrientconcentrations and primary productivity.Nutrient objectives have to be scientificallydefensible; otherwise they will be of littlevalue when it comes to managing andregulating nutrient inputs to streams and riversfrom point and non-point sources.F. Derive nutrient objectives based on the resultsof the statistical analysis and modelling work.For Additional Information, Visit Manitoba Conservation’s Website for Current Issues - Latest Newswww.gov.mb.ca/environ/

Page 4The derivation of the nutrient objective valuescan take one or more of the followingapproaches.! Objectives may be derived on the basis ofinformation obtained from referencestream conditions within each region.! Objectives can be established at levelsbased on predictive relationships betweennutrient concentrations and acceptablelevels of primary productivity. (Thisapproach should consider different wateruse objectives - acceptable levels of algaemay differ depending on water use withinthe stream/river).! Establish nutrient objectives based onrecommendations in the scientificliterature and on existing objectives andguidelines derived for other jurisdictionsin Canada, the United States, andelsewhere.G. Continue to support work being conductedelsewhere in the prairies, and in particular,eutrophication studies being undertaken by theCommittee on Water Quality of the PrairieProvinces Water Board.(2) Objectives Based on Receiving WatersThis approach involves developing objectivesfor waterways based on the effects that streamnutrient loads have on the lakes and reservoirs intowhich they enter.Lake Winnipeg is the recipient of much of thedrainage in the southern half of Manitoba. Sincemost of the waterways that flow into the lake carrysignificant amounts of nutrient, witheutrophication in the southern basin of the lakeperhaps approaching conditions observed in LakeErie in the past century (Wood 1999). It ispossible to reverse or halt this process bydeveloping nutrient objectives for streams whichenter the lake that are based on the carryingcapacity of the lake itself. In doing so the waterquality of the lake and possibly the water qualityof waterways upstream of the lake will beprotected.The derivation of nutrient objectives forsurface waters in southern Manitoba based on thewater quality and carrying capacity of LakeWinnipeg will require extensive studies and datacollection, and detailed statistical analysis andmodelling. The major steps in the processinclude:A. Determine the carrying capacity of LakeWinnipeg.B. Determine the amount of external nutrientloading that is contributed by rivers andstreams that flow into the lake.C. Determine the maximum acceptable nutrientconcentrations for streams entering lakeWinnipeg. This will be based both on thecarrying capacity of the lake and the relativecontribution of each stream to the totalnutrient loading to the lake.D. Develop nutrient objectives for rivers andstreams entering the lake, keeping in mind thatthe objectives have to protect the water qualityof the receiving water, as well as the waterquality and water uses of the watercourseupstream of the lake.For Additional Information, Visit Manitoba Conservation’s Website for Current Issues - Latest Newswww.gov.mb.ca/environ/

Page 5Item 3: Managing Nutrient SourcesSome jurisdictions have already developed, orare in the process of developing a watershed (ordrainage basin) based approach to nutrientmanagement. The watershed approach involvesfirst identifying all of the inputs to the riversystem within a basin or watershed, followed bythe development and implementation of strategiesaimed at reducing these inputs. The watershed orbasin management approach is often multidisciplinaryand requires the cooperation of allstakeholders within the watershed. The approachis in keeping with the overall movement towards amore holistic, ecosystem-based approach toenvironmental management.Nutrient sources that are discrete observabledischarges are called point sources, while sourcesthat are more diffuse and more difficult to quantifyare called non-point sources.Control of Nutrient Loading from PointSourcesPoint sources of nutrients in southernManitoba include wastewater treatment lagoondischarges, sewage and wastewater treatment plantdischarges, urban storm water drains, andchannelled run-off associated with large livestockoperations. Issues and actions to consider in thecontrol of nutrient inputs from point sourcesinclude:A. All point sources of nutrients have to beidentified and any information/data aboutnutrient loading from these point sources hasto be gathered. This information can then beanalyzed/modelled along with existing streamnutrient and flow data to ensure compliancewith the nutrient objectives of the stream.B. In cases where non-compliance occurs,nutrient control measures such as tertiarytreatment (e.g. constructed wetlands) ornutrient reduction technology (e.g. alumapplications) may have to be considered.C. In the case of streams that have multiple pointsources, the sources will be encouraged tocoordinate their discharges in such a way as toensure that stream nutrient objectives are notexceeded and water use is not compromisedduring discharge periods.D. Point source discharges may have to berelocated to minimize negative impacts to thewaterway and to water uses along thewaterway.E. Education awareness campaigns may need tobe initiated that are aimed at reducing nutrientinputs in domestic and industrial wastewater.Control of Nutrient Loading from Non-pointSourcesNon-point source loading refers to nutrientloading from land surface run-off across awatershed or catchment basin. Non-point sourcesof nutrients in southern Manitoba include surfacewater runoff from urban areas, fertilized fields,pastures, and livestock holding areas. Run-offfrom non-fertilized lands can also be considered anon-point source of nutrients simply because ofthe naturally high soil fertility in some parts ofsouthern Manitoba. Other non-point sources ofnutrients include atmospheric deposition andgroundwater seepage.In general, nutrient inputs to a waterway fromnon-point sources tend to be extremely variable,intermittent, and difficult to predict and control.This makes assessing their contribution to theeutrophication of a given waterway much moredifficult to ascertain. Some management practicesthat help to control non-point source loading ofnutrients to waterways include:A. Control of runoff waters and soil erosion fromagricultural and urban areas through improvedmethods of landscaping.B. Use of precision farming practices to limit theamount of excess chemical fertilizers andmanure applied to cultivated land.C. Preservation or re-establishment of riparianvegetation along waterways.D. Restricted access of cattle and other livestockto waterways.For Additional Information, Visit Manitoba Conservation’s Website for Current Issues - Latest Newswww.gov.mb.ca/environ/

Page 6E. Increased awareness of eutrophication in ruralareas with emphasis on the need to change oralter farming practices.F. Increased cooperation, communication, andeducation between government (all levels),producers, conservation groups, and otherconcerned parties.Item 4 – Develop a Geographic Information System(GIS) for the Nutrient Management StrategyThe development of a GIS is an importantcomponent of the nutrient management strategy.A GIS allows one to create customized maps withgeo-referenced data. Using the GIS will allowwater quality data to be displayed, interpreted, andmodeled on a geographic scale (spatial analysis).This will help facilitate better decision making onthe part of water managers and bettercommunication of the data and management plansto regulators, elected officials, and the generalpublic.All point sources that discharge to water(licensed or otherwise), associated data, andambient water quality data, should be included inthe GIS. This information will be gleaned fromEnvironment Act Licences, client files, the WaterQuality Management Section database, andhistorical records, and by conferring directly withDepartment staff in the Municipal and IndustrialApprovals Section and in the regional offices.Item 5 – Other Issues and ConsiderationsOther issues and items to consider in thedevelopment of a nutrient management strategyinclude:A. Public perceptions of water quality can differsignificantly from place to place such that thelevels of primary productivity that areconsidered tolerable in one locale may beregarded as overly excessive in another locale.B. Establishing objectives for nutrients with thegoal of keeping algal and macrophyte growthbelow “nuisance” levels for aesthetic reasonsmay not adequately protect aquatic life,preserve ecosystem structure, or limit bluegreenalgae toxin production. Because of this,the development of nutrient objectives willalso have to consider the various types ofwater usage.C. Chemical and physical features may varyconsiderably between reaches along the samewaterway. This is particularly true for someof the large rivers in the province and maynecessitate the division of such waterwaysinto segments with each segment having itsown set of nutrient objectives.D. Many of the rivers and streams in southernManitoba originate from outside of theprovince. As such, a nutrient strategy forsouthern Manitoba will have to seek somelevel of inter-provincial and international cooperationand input.Schedule of Activities (tentative)The steps required to derive nutrientobjectives and develop a nutrient managementplan are quite complex and will require asignificant commitment of time and energy fromthose involved in the process. The following is atentative schedule of activities geared towards thedevelopment of a nutrient management strategythat will be undertaken over the next three years.• Finalize outline of Nutrient ManagementStrategy: July 2000• Review and report of WQMS database anddevelop list of core variables for monitoring:September - April 2000• Begin development of a carrying-capacitymodel for Lake Winnipeg: January 2000 -June 2000• Develop monitoring plan for sampling during2000 growing season (May – October): May2000• Develop a GIS for the nutrient strategy:September 1999 – on-goingFor Additional Information, Visit Manitoba Conservation’s Website for Current Issues - Latest Newswww.gov.mb.ca/environ/

Page 7• Explore nutrient objective derivation optionsin greater detail and decide on appropriatemethods based on data interpretation, GIS andstatistical analysis, research in the literature,methods used in other jurisdictions, and inconsultation with professional colleagues,conservation groups, stakeholders, and otherinterested parties: May 2000 – December2000.• Explore management options (throughresearch and consultation) that can be used tohelp reduce inputs of nutrients to surfacewaters: May 2000 - ongoing• Continue to establish and run focusedmonitoring programs to collect data (wherelacking) to be used in the development ofnutrient objectives: January 2001 - future• Establish nutrient objectives: 2002 –2003• Using the objectives as a guide, develop andimplement a nutrient management plan. Theplan should emphasize the nutrient abatementoptions that are available to nutrientdischarges and run-off to surface waters, butshould also include a set of regulations toencourage compliance with the nutrientobjectives and the management plan.Sources of InformationAlberta Environmental Protection. 1997. AlbertaAmbient Surface Water Quality InterimGuidelines. Alberta Environmental Protection.Environmental Assessment Division.Edmonton, AB.www.gov.ab.ca/env/dept/facts/watqualt.html6 pp.ANZECC & ARMCANZ. 1999. Australian andNew Zealand Guidelines for Fresh andMarine Water Quality (Draft). Australia andNew Zealand Environment and ConservationCouncil (ANZECC) and the Agriculture andResource Management Council of Australiaand New Zealand (ARMCANZ). Canberra,NSW, Australia.www.environment.gov.au.html.CCME. 1987 (plus updates to 1994). CanadianWater Quality Guidelines. Canadian Councilof Ministers of the Environment.Environment Canada and Health Canada.Ottawa, ON, Canada.CCME. 1999. Canadian Environmental QualityGuidelines. Canadian Council of Ministers ofthe Environment. Winnipeg, MB, Canada.Carr, G. M. and P. A. Chambers. 1998. Spatialand Temporal Patterns in Nutrients and AlgalAbundance in Alberta Rivers. ContributionNo. 98-225. National Water ResearchInstitute, Canada Centre for Inland Waters,Environment Canada. Saskatoon, SK, Canada.(Prepared for the Prairie Provinces WaterBoard, Regina SK). 96 pp.Chambers, P. A. 1996. Nutrient Enrichment inthe Peace, Athabasca, and Slave Rivers:Assessment of Present and Future Trends.Northern River Basins Study Synthesis ReportNo. 4. Northern River Basins Study,Edmonton, AB, Canada. 107 pp.Daniel, T. C., A. N. Sharpley, J. L. Lemunyon.1998. Agricultural phosphorus andeutrophication: A symposium overview. J.Environ. Quali. 27:251-257.Canadian Department of Mines and NaturalResources. 1969. Canada Land InventoryProject: Province of Manitoba WatershedDivisions (map). Winnipeg MB.Dodds, W. K., V. H. Smith, and B. Zander. 1997.Developing nutrient targets to control benthicchlorophyll levels in streams: A case study ofthe Clark Fork River. Water Res. 31:1738-1750.Ecological Stratification Working Group. 1995(update to September 1997). A NationalEcological Framework for Canada. Centrefor Land and Biological Resources Research,Research Branch, Agriculture and Agri-FoodCanada, and Ecozone Analysis Branch, Stateof the Environment Directorate, EnvironmentCanada. Ottawa, ON, Canada.http://www1.ec.gc.ca/∼ecozones/defaultEMD (Environmental Management Division).1980. Proposed Classification of Manitoba'sSurface Water: Red River Principal WatershedFor Additional Information, Visit Manitoba Conservation’s Website for Current Issues - Latest Newswww.gov.mb.ca/environ/

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Page 10Environmental Protection Agency.Washington, DC. www.epa.gov/ost. 25 pp.USEPA. 1999c. National Nutrient AssessmentStrategy: An Overview of Available Endpointsand Assessment Tools. Nonpoint SourcePollution Control Program. Office of Water,United States Environmental ProtectionAgency. Washington, D.C.www.epa.gov/OWOW/NPS/proceedings/overview. 65 pp.Williamson, D.A. 1983. Surface Water QualityManagement Proposal. Volume 2: WatershedClassifications. Water Standards and Studies,Manitoba Department of Environment andWorkplace Safety and Health. Winnipeg,MB, Canada. Report #83-3. 6 pp.Williamson, D.A. 1988. Manitoba Surface WaterQuality Objectives. Water Standards andStudies, Manitoba Environment andWorkplace Safety and Health. Winnipeg,MB, Canada. 47 pp.Williamson, D.A. 2000. Draft Manitoba WaterQuality Standards, Objectives, andGuidelines. Manitoba Conservation.Winnipeg MB.Wood, J.A. 1999. Water Quality in the PrairieEcozone. Ecological Research Division,Environmental Conservation Branch, Prairieand Northern Region, Environment Canada.Regina, SK, Canada.www.mb.ec.gc.ca/english/water/wqprairie.Yee, B. 1999. Personal communiciation (via GISUSERS TIPS and TECHNIQUES mailinglist). Brian Yee, P. Eng.. Head, GIS Section,Ecological Research Division Prairie andNorthern Region, Environment Canada. 2365Albert St., Rm 300, Regina, SK, Canada.For Additional Information, Visit Manitoba Conservation’s Website for Current Issues - Latest Newswww.gov.mb.ca/environ/