Holer

S U B M I T T E D A P R I L 9 2 0 1 3

Nitrogen and Phosphorus Loading into Lake

Winnipeg via the Assiniboine and Red Rivers: 1994-2001

TANNER GRESCHNER 6853305 RILEY HOLE 7641313

MEAGAN GLOWA 7640460 CARRISSA LYNN KYLE-OTTENSON 7639294

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TABLE OF CONTENTS

1 EXECUTIVE SUMMARY 3

2 INTRODUCTION 4

3 METHODS 7

4 RESULTS 10

5 DISCUSSION 13

6 CONCLUSION 15

7 LIST OF FIGURES 17

8 REFERENCES 18

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1 EXECUTIVE SUMMARY It can be argued that Manitoba’s greatest asset is the abundance of

freshwater found within the province. Lake Winnipeg is the eleventh biggest lake in

the world and is part of the most undeveloped watershed, which spans from Alberta

to Minnesota to Northern Ontario, in Canada, yet Lake Winnipeg is one of the most

threatened lakes on Earth. The escalating threat is in part the result of nutrient

loading from the Assiniboine and Red Rivers, two of the major waterways feeding

Lake Winnipeg. Excess nitrogen and phosphorus are being accumulated in the lake

because of an intensive agricultural industry throughout the Prairie Provinces and

northern states. Excess phosphorus in the lake does not allow the excess nitrogen to

be absorbed, which results in large and toxic algae blooms.

This report will collect and analyze data on nitrogen and phosphorus loading

in the Assiniboine Rivers, based on watershed areas, from 1994 to 2001. By locating

water-monitoring stations along these rivers based on their proximity to municipal,

industrial and agricultural centers, samples could be collected tri-monthly so that

total phosphorus and total nitrogen could be calculated for both rivers. From the

data it can be seen that the Red River and including watershed contributes a larger

amount of total nitrogen and total phosphorus to Lake Winnipeg annually from

1994-2001.

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The importance of a healthy Lake Winnipeg is vital in sustaining the

economic, social and environmental security of Manitoba. We conclude our study by

encouraging further, exhaustive monitoring and research on the Assiniboine and

Red Rivers, which will help to understand and inhibit dangerous levels of nutrient

loading into Lake Winnipeg.

2 INTRODUCTION

Manitoba is home to many lakes and rivers. Surface waters account for

sixteen percent of the total area of Manitoba. Some major Manitoban rivers include

the Red River and the Assiniboine River. The Red River is a north flowing river that

established in the bed of glacial Lake Agassiz that receded approximately eight

thousand years ago. It is 877 kilometers in length

and is approximately fifteen feet deep depending

on the location. The Red River runs through

Minnesota and North and South Dakota of the

United States and into Manitoba, Canada where it

connects with the Assiniboine River. The

Assiniboine River is 1,070 kilometers in length and

brings water from all across the prairies, as far as

the Rocky Mountains, and together the Red River and Assiniboine River make the

Red River watershed. Both rivers empty into Lake Winnipeg through the Red River

watershed and eventually flow into Hudson’s Bay and become part of the Arctic

Ocean.

Figure 1: Assiniboine River Map

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The Red River watershed collects water from approximately 280,000 square

kilometers and empties it into Lake Winnipeg. There are nine major watersheds that

are located in the Southern half of Manitoba with Lake Winnipeg being the recipient

of the majority of the drainage from watersheds. Lake Winnipeg is the tenth largest

freshwater body in the world and the largest hydroelectric reservoir in North

America. It is 436 Kilometers in length and can reach depths as deep as 36 meters in

some areas. Many residents in the area depend on the lake for drinking water and

fish, but over the past few decades the water quality of the lake has depleted with

major blame on the effects of excess nutrient loading. Excess nutrient loading is

causing an increase in algae blooms on Lake Winnipeg due to an increase in

nitrogen and phosphorus concentrations, which are likely associated with the inflow

of nutrients from the Red and Assiniboine Rivers (Yi, Y, Gibson, J, Helie, JF, Dick, T,

2010).

Nutrient loading in lakes and rivers is an important issue in water quality.

Excess nutrients in water can lead to increased algae and aquatic plant growth

which produce toxins that can cause

off tastes and odors, and decrease

biodiversity in the water (Mayer, B,

Wassenaar, L, 2012). Two important

nutrients that are involved in nutrient

loading are Nitrogen and Phosphorus.

Both of these nutrients are essential to

plant growth. Phosphorus is needed in the process of photosynthesis and nitrogen is

[Fig. 2] Algae Blooms on Lake Winnipeg

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an essential nutrient for all living organisms. Nitrogen and phosphorus can

contribute to nutrient loading in lakes and rivers in many different ways, either

through anthropogenic sources or naturally. Some anthropogenic contributions to

nutrient loading could include factories or agricultural processes that result in

effluent discharge into nearby water sources (Schindler, D, Hecky, R, McCullough, G

(2012). In Manitoba fifteen percent of the land is used for agricultural activities.

Fertilizers are commonly used in agriculture, which can increase the potential for

nutrient loading to surface waters in surrounding areas due to runoff. Surface runoff

from non-fertilized fields can also be a problem due to naturally rich soils. There are

fourteen rivers in Manitoba, including the Rat River and Morris River, that drain

farmland on the east and west side of the Red River Valley into the Red River. A

natural process that could contribute to nutrient loading would be rain. Nitrogen

and Phosphorus could be directly deposited on land and water by rain. Nitrogen and

Phosphorus can also be found in sediment particles in streams. The particles can be

picked up by the current and moved further downstream changing the

concentration of nutrients in the stream. A brief introduction of the calculations for

nitrogen and phosphorus found in water samples is described below.

Total phosphorus concentrations (TP) and total nitrogen concentrations

(TN) are used as the measurement for phosphorus and nitrogen respectively. Total

phosphorus is not an indication of the amount of phosphorus present in a sample of

water but rather a measurement of the amount of phosphorus that is potentially

available to plants in the water. To determine TP the dissolved and particulate

forms of phosphorus are added together, and to determine TN it is the combination

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of total organic nitrogen (TON) and total inorganic nitrogen (TIN). TON is found by

measuring the total Kjeldahl nitrogen content (TKN), which consists of TON and

ammonia, so by subtracting the ammonia from TKN you are left with the

measurement for TON. TIN is simply found by adding together the ammonia

concentrations and the nitrite-nitrate concentrations in a water sample. The total

measured stream nutrient load (TMSNL) calculates the amount of nutrients present

in a stream at a given time. Processes that directly influence TMSNL are referred to

as within-stream processes, such as erosion, and processes that indirectly influence

TMSNL are referred to as watershed processes, such as runoff. To calculate TMSNL

the nutrient concentration of the stream is multiplied by the flow rate of the stream

in a particular area. The focus of this experiment is placed on the Red River

watershed. Nitrogen and phosphorus concentrations are found for both the Red

River and the Assiniboine River between the years of 1994 to 2001 to determine

whether the Red River and the Assiniboine River contribute different amounts of

nutrients in the form of nitrogen and phosphorus per square kilometer to the Red

River watershed, and in turn to Lake Winnipeg.

3 METHODS

Several permanent water Monitoring stations were selected along the

Assiniboine River and the Red River. The maps [Fig. 3,4] show where stations were

located throughout the two rivers. The population to be sampled was nitrogen and

phosphorus load in the two rivers, the sampling frame being all water within the

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Assiniboine and Red Rivers. The decision of where water-monitoring stations were

placed was based on a non-probability, convenience-sampling method due to

variability in river geography. Stations were also set up based on proximity to

agricultural land, areas of municipal and industrial effluent and other sites that have

varying effects on nitrogen and phosphorus load within the two rivers.

Sampling for the two rivers went as followed; during months when the two

rivers were not frozen over (May – November) samples were collected three times

monthly through the use of these water sampling stations. At these stations water is

collected approximately 2-3 meters from the river bottom using a thoroughly

cleaned and rinsed plastic bucket. Water was then placed in four bottles and was

taken to a lab to be analyzed for total nitrogen and total phosphorus load (mg/L).

Monthly data was kept on record in the lab.

During months when the two rivers were frozen (December – April), holes

were drilled through the ice using an auger and water samples were extracted

though these holes using four thoroughly cleaned and rinsed plastic bottles. Samples

were also collected three times monthly. Total nitrogen and total phosphorus

(mg/L) were measured and recorded as it was in the non frozen months and data

records were kept on file.

This sampling process continued consistently from 1994 to 2001. From this

collection of monthly data throughout the years, annual averages were calculated

for total phosphorus and total nitrogen load in the Assiniboine River and the Red

River separately.

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[Fig. 3] Red River water quality monitoring stations ( ). Gov. 2002

[Fig. 4] Assiniboine River water quality monitoring stations ( ). Gov. 2002

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4 RESULTS

In order to obtain values of some significance, data had to be combined. Data

was supplied in the form of tons per year of either phosphorus or nitrogen nutrient.

We wanted to focus on the total value of eutrophication causing nutrients that enter

Lake Winnipeg via the Red River and Assiniboine River. In order to obtain these

values we had to add the total nitrogen load from 1994 to 2001 to the total

phosphorus load for the same time frame. [Fig. 5] below displays the total

phosphorus and nitrogen loads for each station along the two rivers and for each

year, starting at 1994 and ending at 2001. The figure also displays the mean and

standard deviation of the total nutrient levels present in both the Red and

Assiniboine rivers.

The best estimate for the two separate nutrient loads should be compared before

the two rivers merge at the Forks in Winnipeg Manitoba. The last gauging station

before the Assiniboine meets the Red River is at the Headingly location

approximately 21.5 kilometres according to Google Maps. The last station on the

Total TN and TP (t/year)

Assiniboine River 1994 1995 1996 1997 1998 1999 2000 2001 Mean s

At Kamsack 252 1888 684 593 224 319 167 540 583.375 494.0049342

At Brandon 1460 4768 3377 2222 1286 3973 968 3630 2710.5 1246.542062

At Treesbank 1606 5236 3589 2397 1596 4397 1424 4219 3058 1313.143472

At Portage Spillway 1765 5537 3856 3072 3090 5767 2439 5185 3838.88 1325.94448

East of Portage 1920 5787 4082 3096 3536 6625 2641 4907 4074.25 1417.158954

At headingley 2050 5255 4209 3991 4494 6524 2750 5280 4319.13 1265.880145

Red River

At Emerson 15728 21181 20488 26872 22338 24765 16959 23830 21520.1 3345.130505

At St. Norbert 19165 29645 28942 27564 28220 30358 18271 31309 26684.3 4462.219322

At Selkirk 24782 40535 38976 46047 39569 28106 27241 45099 36294.4 7379.251391

[Fig. 5] Total nutrient loading for gauging stations along the Assiniboine and Red Rivers

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Red River before it merges with the Assiniboine River is at the St. Norbert gauging

station, which is approximately 16.5 kilometres from the Forks also calculated by

Google Maps. The readings from these two gauging stations where used to conduct

the proper tests. It makes sense that the gauge stations up stream have smaller

nutrient loads, Kamsack station is the furthest station up the watershed the values

are lower than other stations because less accumulation of nitrogen and phosphorus

nutrients has taken place. There is a wide inter-annual variation between the

amounts of nutrient load in the two rivers. The range in load amount for the

Assiniboine River is 4474 tons of nutrients, with 1994 having the smallest value

2,050 tons and 1999 with the largest amount of nutrients at 6,524 tons. The Red

River carries a significantly larger load of nutrients, the lowest amount occurred in

2000 at 18,271 tons. The largest amount of nutrients occurred in 2001 with a mass

of 45,099 tons giving the red a range of 26,828 tons. From the combined total

phosphorus and total nitrogen amounts it is clear that there are more nutrients

flowing into Lake Winnipeg that originated in the Red River. The purpose of our test

was not to look at the amounts of the nutrients but to look at the nutrients per

square kilometer of each rivers total watershed area. Calculated in previous work

the total watershed area for the Assiniboine River is equal to 41,500km2, and the

watershed area for the Red River was 127,000km2 (Bourne). With this information

further statistics could be derived to calculate nutrient amounts per square

kilometer for each watershed. The data is presented below in [Fig. 6].

[Fig. 6] Tonnes of nutrients per watershed area, at the last two gauging stations for each river.

TN&TP loads/km2 1994 1995 1996 1997 1998 1999 2000 2001

Assinaboine 0.049398 0.126627 0.10142 0.096 0.108 0.157 0.066 0.127

Red River 0.150906 0.233425 0.22789 0.217 0.222 0.239 0.144 0.247

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The data above in figure 2 represents the total tonnes of nutrients per square

kilometer of the respective watershed area. In order to compare the results of the

data in figure 2, a program by the name of Statistical Product and Service Solutions

(SPSS) was used. The data entered in the SPSS program is available for analysis and

interpretation. A paired sample t-test was run in SPSS to acquire the correct

information about the gathered data. The test contains a 95% confidence interval

and a significance value of 0.05. The results of the test run are located below in [Fig,

7].

From figure 3 above we are interested in one of the values; we are interested in the

Sig. (2-tailed) value or p-value as commonly referred to. Stated earlier in the paper

we predict that the Red River and the Assiniboine River will contribute the same

amount nutrients in the form of nitrogen and phosphorus per km2 of the watershed

between the years of 1994 to 2001. To test if this hypothesis is correct we need to

interpret the p-value, if the p-value is less than the significance value (α) then there

is enough evidence to reject the null hypothesis. The p-value for our test is a very

[Fig. 7] SPSS results

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small number less than 0.000, this means that our p-value is less than α (0.05). This

means that we reject the null hypothesis that the Red and Assiniboine River

contribute the same amount nutrient mass to Lake Winnipeg in the form of nitrogen

and phosphorus per square kilometer of the watershed than the Assiniboine River.

To understand this fully there is sufficient evidence to support that the Red River

and Assiniboine River contribute the different amounts of nutrients per square

kilometer to Lake Winnipeg.

5 DISCUSSION

Nitrogen is a naturally occurring nutrient that is used and reused by plants in an

ecosystem with minimal leakage into surface and ground water. When nitrogen is

applied to land in amounts greater than the amount that can be used by crops,

concentrations in rivers tend to increase. Excess nitrates are not toxic but they can

result in large algae blooms, which can decrease oxygen levels, consequentially

harming fish and other aquatic life. Animal waste, septic systems and atmospheric

deposition, as well as fertilizer, contribute to excess nitrogen. Saturated phosphorus

levels in water systems can also lead to over stimulated algae growth.

It is important to look at the factor of nutrient loading in the rivers that lead to

major lakes. When you look at the dispersion of where nitrogen and phosphorus

enter Lake Winnipeg it makes interpreting the amount of these two nutrients

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coming from the Red River. [Fig. 8] below shows the amount of total nitrogen on the

right and total phosphorus entering Lake Winnipeg from each respective source.

[Fig. 9] Mean TN & Mean TP

[Fig.8] illustrates the importance of understand the aspects that lead to the large

amount of nutrient addition to the lake via the Red River, and the Assiniboine River

is a critical part of the Red River. Lake Winnipeg was named the most threatened

lake of the year by an international environmental organization from Germany

called Global Nature Fund (Radolfzell, 2013). It got this title due to increasing

pollution amounts from agricultural run-off and sewage discharges. The pollution,

in turn, creates an overabundance of phosphates, which results in the formation of

blue-green algae, which are toxic to humans and throw the lake's ecosystem off-

balance. There is great need to understand the workings of the lake and all factors

that lead to the nutrient loading of the rivers that lead to the lake.

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6 CONCLUSION

Based on the findings of our study we strongly recommend continued research

regarding nitrogen and phosphorus loading into Lake Winnipeg via the Assiniboine

and Red Rivers, enabling the Manitoba government to develop a provincial and

national strategy to decrease hazardous nutrient loading into the worlds eleventh

largest freshwater lake. Agricultural, industrial and municipal activity all

contributes to this problem. Their activity must be controlled and accounted for, as

to not further damage the volatile Lake Winnipeg.

The US state of Florida has began to implement a strategy to reduce nitrogen and

phosphorus loading in their waterways by introducing a water quality credit trading

program (Florida DofEP, 2010). The program is similar to the European Unions

Emission Trading System where emission allowances can be bought or sold by

traders.

Another strategy is being implemented by the state of Iowa to reduce nutrient

loading into the Gulf of Mexico via the Mississippi River and it’s Iowan watershed.

The state has set up the Water Resources Coordinating Council to help centralize

water quality strategies and one of their first objectives is to determine goals the

state wants to achieve in reducing harmful activity in watershed areas. Iowa intends

to technologically advance their wastewater treatment plants by utilizing the

National Pollutant Discharge Elimination System permit process (Iowa Department

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of Agriculture and Land Stewardship, 2012). The state is also focused on prioritizing

initiatives in research, technology, education and public recognition to maximize

their potential to reduce nutrient loading.

Since the mid-1980s Denmark has also been setting specific reduction targets and

innovative strategies to reduce nitrogen and phosphorus loading. It is clear this

issue is a global one and has the attention of major world leaders. Since Manitoba

has such an abundance of freshwater at risk it is important that the government

takes major strides to become a national and global leader in water quality

initiatives and innovations.

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7 LIST OF FIGURES

FIGURE 1 – Bower, S (May 15 2011). The Assiniboine River Flood of 2011: Without Precedent. Retrieved on April 5 2013 from: http://niche- canada.org/node/10000 FIGURE 2 – Science Daily (July 24 2008). Trying To Save World's Lakes: Controlling Nitrogen Can Actually Worsen Problems. Retrieved on April 5 2013 from: http://www.sciencedaily.com/releases/2008/07/080721173754.htm FIGURE 3 – Bourne, A, Armstrong, N, Jones, G (November 2002). A Preliminary

Estimate of Total Nitrogen and Total Phosphorus Loading to Streams in

Manitoba, Canada. Retrieved on March 1 2013 from:

http://www.gov.mb.ca/conservation/eal/registries/4864wpg

ww/mc_nitrophosload.pdf

FIGURE 4 – Bourne, A, Armstrong, N, Jones, G (November 2002). A Preliminary

Estimate of Total Nitrogen and Total Phosphorus Loading to Streams in

Manitoba, Canada. Retrieved on March 1 2013 from:

http://www.gov.mb.ca/conservation/eal/registries/4864wpg

ww/mc_nitrophosload.pdf

FIGURE 5 – SPSS Data - Total nutrient loading for gauging stations along the Assiniboine and Red Rivers FIGURE 6 – SPSS Data - Tonnes of nutrients per watershed area, at the last two gauging stations for each river FIGURE 7 – SPSS Data – Paired Samples Test

FIGURE 8 – SPSS Data – Total TN & Total TP

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8 REFERENCES

Yi, Y, Gibson, J, Helie, JF, Dick, T (2012). Estimating nutrient production from human activities in sub catchments of the Red River. Journal of Hydrology [Vol.383, p223-232] Mayer, B, Wassenaar, L (2012). Isotopic characterization of nitrate sources and transformations in Lake Winnipeg and its contributing rivers. Journal of Great Lakes [Vol.38, p135-146] Schindler, D, Hecky, R, McCullough, G (2012). The rapid eutrophication of Lake Winnipeg: Greening under global change. Journal of Great Lakes Research. [Vol. 38, p.6-13] Bourne, A, Armstrong, N, Jones, G (November 2002). A Preliminary Estimate of Total Nitrogen and Total Phosphorus Loading to Streams in Manitoba, Canada. Retrieved on March 1 2013 from: http://www.gov.mb.ca/conservation/eal/registries/4864wpg ww/mc_nitrophosload.pdf

Armstrong, Nicole. "ASSINIBOINE RIVER WATER QUALITY STUDY." Manitoba conservation (2002):http://www.gov.mb.ca/waterstewardship/water_quality/quality/assiniboine_river_water_quality_report_2002_10.pdf. Web. 7 Apr. 2013.

Radolfzel (February 2 2013). Global Nature Fund. Threatened Lake of the Year 2013: Lake Winnipeg in Canada. Retrieved on March 15, 2013 from: http://www.globalnature.org/ThreatenedLake2013 Florida Department of Environmental Protection (October 2010). Pilot Water Quality Credit Trading Program for the Lower St. Johns River. Retrieved on March 22 2013 from: http://www.dep.state.fl.us/water/wqssp/docs/WaterQualityCreditReport-101410.pdf Iowa Department of Agriculture and Land Stewardship (November 2012). IOWA NUTRIENT REDUCTION STRATEGY: A science and technology-based framework to assess and reduce nutrients to Iowa waters and the Gulf of Mexico. Retrieved on March 22 2013 from: http://www.nutrientstrategy.iastate.edu/sites/default/files/documents/NRSfull.pdf

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