Solutions to Nitrogen Pollution: Solving the Cranberry Puzzle

Solutions to Nitrogen Pollution: Solving the Cranberry Puzzle

April 14, 2015

Rachel W. Jakuba, Buzzards Bay CoalitionChris Neill, Marine Biological Laboratory

Carolyn DeMoranville, UMass Cranberry StationKirby Gilmore, Gilmore Cranberry Company

Logistics and Details

• Agenda• Evaluation – please fill out and return.• Upcoming workshops

– May 27 – Solutions to Nitrogen Pollution: The Wareham Case Study.

– June 11 –Water Words that Work.

• www.savebuzzardsbay.org/DecisionMakers

Outline

• Rachel – Background & study methodology• Chris – Study results• Carolyn – Other research & next steps• Kirby – Perspective from a grower

What is Nitrogen Pollution?

• Nitrogen is a naturally occurring element• Nitrogen is a key component of cellular building blocks

• Nitrogen usually controls how much algae grow in coastal waters

• Too much nitrogen is damaging to coastal ecosystems

What is Nitrogen Pollution?

Examples of Nitrogen Pollution

Rusty Tide in the Wareham River (Tempest Knob boat ramp, 2012)

Examples of Nitrogen Pollution

Nitrogen pollution management

• Many coastal waters around Buzzards Bay are listed as impaired for N on 303(d) ‘Dirty Waters’ list

• MA is required to developed TMDLs for these waters that include plans for reducing N

• Massachusetts Estuaries Project develops a target N threshold that a specific estuary can handle and sources of N to that estuary

• Local Management is critical

Wareham Nitrogen Consensus

• Collaboration of Wareham thought leaders who all believed they had a direct interest in seeing N pollution reduced and Wareham coastal water quality restored

• Series of nine facilitated meetings focusing on two N pollution sources: wastewater and cranberry agriculture

• Group collaboratively developed an Action Plan

• One action was to launch a scientific study to better determine N loadings from different types of cranberry bogs

Agriculture as a nitrogen source

• Agriculture can be a significant contributor to N in coastal waters in SE MA, though wastewater is typically the largest source of N

• Cranberry is the dominant form of agriculture in the Buzzards Bay watershed

• While a low relative rate of fertilizer compared with other crops they are closely connected to waterways

Agriculture as a nitrogen source

Distribution of N sources

• In some SE MA subwatersheds cranberry agriculture can be a significant contributor of N to coastal waters

Agawam River subwatershed Wankinko River subwatershed

Data from Massachusetts Estuaries Project (Howes et al. 2013)

Understanding the effect of bogs

• Limited quantitativeinformation – only two scientific studies in SE MA on N loss from bogs

• Values from the two studies range by over 3‐fold for N loading

• Uncertainty in loading models can lead to unfulfilled or unexpected outcomes from actions taken

• Biggest concern is movement of N in surface water• Extent of groundwater pathway is unknown

Reducing Uncertainty

• Partnership between Coalition, UMass Cranberry Station, MBL, Town of Carver, Cape Cod Cranberry Growers’ Association

• Study 2 common bog configurations for 2 flood seasons (two harvests, two winter floods)

• Funded by DEP and BBNEP

Long Tail Pathway

Closed Loop

Basic study design

• Measure N & P in water before and after it is on the bog• Groundwater up and down gradient

• Surface water in and out• Measure surface water levels to estimate flow

• Combine N & P concentration data with water flow estimates to calculate mass of N & P leaving the bogs

Example site

Chris Neill ‐ Results

Groundwater Nitrogen

Closed Loop Long Tail

Groundwater Phosphorus


Surface Water ‐ Harvest Nitrogen


Surface Water ‐ Harvest Phosphorus


Surface Water – non‐flood Nitrogen


Surface Water – non‐flood Phosphorus


Flux during floods

Comparison to Previous Study

Nitrogen fluxes to the Wareham River Estuary

Fluxes in perspective

Assumptions:

Watershed fluxes: DeMoranville & Howes 17% from bogsThis study 19‐22% from bogs

• Annual fluxes in current study are in the same proportion to harvest floods as in DeMoranville & Howes

• Same proportion of flow‐through and more modern bogs as in MEP

• Same attenuation (8‐17%) in streams and rivers

• Concentrations and forms of nitrogen and phosphorus in input and output water were variable and made it hard to define an "average" bog

• Phosphorus concentrations tended to be highest in outflowing water during harvest floods

• Net nutrient fluxes based on estimates of water flow and measured input and output concentrations were in the range measured by other studies and provide confidence that we correctly estimated the range of potential fluxes

• Scaling fluxes from cranberry bogs to the whole watershed leads to conclusions similar to those reached in the MEP

• Future work should better quantify water fluxes and increase sampling frequency to better capture changes to concentrations during periods of high water movement.

Conclusions

Other Research and Next Steps

Carolyn DeMoranvilleUMass Cranberry Station

UMass Cranberry Station

• Casey Kennedy, USDA ARS– Continuous monitoring approach– Multiple sites– P and N

• Coalition / MBL / Cranberry Station group– Lessons from Kennedy outcomes– Continuous approach to floods and storm events


Research Projects


Casey Kennedy – Several ongoing studies

Continuous Monitoring


Continuous Monitoring


Measurement of Volumetric Flow

Kennedy studies – P in floods

• Winter flood is 4x lower in P compared to harvest

• Newly renovated bogs export less P in floods• TDP – mainly from soil pore water• TPP – ditch sediment mobilization


Kennedy studies – P in floods

Renovated beds export less P in harvest flood

TDP peaks: 0‐5 cm below bed surface; ~25 cm below bed surface

TPP peak: level of ditch sediments

Not all of the flood water is equal!!

Same site as previous slide. Water numbers are N in kg/ha in harvest flood only.

Blue items below are unknowns.N comes into a bog in fertilizer, rain, surface water and groundwater discharge.N leaves in the berries, surface discharge, and groundwater recharge. N is stored in the soil and plants.


Kennedy studies – N in floods

TN rise associated with drainage reaching 50 cm below the surface – combinationof pore water and ditch sediments

Ditch waterFlood release water

Water level 50 cmbelow surface


“Wisconsin Style” Bog – yearly studyTD3 TD4

TD2 TD1

FLUME

‐ Cranberry Bed ‐ Drainage Ditch

‐ Sampling site

‐ Discharge Flume

‐ Input Flume ‐ Flow Direc on of ditch

‐ Drainage le


Hydrologic Inputs

1.48

4.10

6.50

1.17

irrigation

precip

flood input

Input from adjacentbed


0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

Feet

(n

orm

aliz

ed t

o 5

acr

e b

ed)

Surface Water Discharge: Storms Vs. Harvest Flood

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

cub

ic f

eet

per

sec

ond

August Storm Event ‐ Flow

0123456789

cub

ic f

eet

per

sec

ond

2013 Harvest Flood Discharge

0

5

10

15

20

25

30

35

TDN

NH4

NO3+NO2

DON

Net Export (kg)

0.454

0.433

-0.065

0.086

0

20

40

60

80

100

TDN

NH4

NO3+NO2

DON

Net Export (kg)

2.93

0.02

0.16

2.75

August storm

Harvest


Net Export of Storms and Flood

2.414

2.932

TDN (kg)

TotalStorms

HarvestFlood

0.985

2.750

DON (kg)

TotalStorms

HarvestFlood


The future

• Partner group – Will continue study of sites, funding

from the EPA via Coastal Zone Management

– Methods modified to more continuous approach: lessons from other projects

– Focus on floods AND big rain events– Develop better numbers for the Mass

Estuaries model based on bog configurations


The future

• Kennedy – Annual nutrient budgets – but…..– Models

• Hydrogeology• Placement in

landscape


The future

• Cranberry StationIn addition to research:– Use research to

formulate extension recommendations

– Example: Focus on critical portions of events

Kirby Gilmore, Cranberry Grower

Questions & Discussion

Solutions to Nitrogen Pollution: Solving the Cranberry Puzzle

Environment

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