willard spur: 2011 hydrology and nutrient loads

Development of Water Quality Standards for Willard Spur

2011 Hydrology & Nutrient Loads

Willard Spur Science Panel

April 5, 2012

Photo:Josh Noble

What was our objective for 2011?

• Understand the sources, quantity, timing, and mechanisms of water and nutrient loading

• Relative contribution of the POTW

Note: Recognized that 2011 was potentially a wet year

• April 2011 snowpack: 185% of normal• April 2012 snowpack: 65% of normal

What we did in 2011

• Mapped and measured inflows• Monitored nutrients in inflows• Measured outflow• Monitored weather• Monitored water surface elevations

Something to consider….

• What does the data mean in the context of our overall objectives?

• How does this influence what we do in 2012?

Overall Inflows (2011)

Willard Bay

Bear River @ Corinne

BRMBR

Water levelDid Willard Spur close off in 2011/2012?

“weir”

BRMBR Inflows (2011)

Residence Time of Water

Month Full Volume RT(days)

2/3 Volume RT(days)

June 4 3August 14 9

September 17 11October 14 9

Note: Estimate assumes constant pool elevation

How did 2011 compare to recent record?

Apparent elevation where GSL changes salinity of Willard Spur = 4201.8ft

Observations

• 2011 represented a very wet year– Does not appear to have “closed”, rare

event since floods of 1980’s• Bear River most significant source of

flow followed by Willard Bay, Harold Crane WMA

• Residence times increased

Nutrient Loads

• Estimated from flow volume and discrete water quality samples (~1/mth)– LOADEST model requires more sample

points than what we have– Used spreadsheet to estimate preliminary

loads– Still trying to address discrepancies in flow

data for Harold Crane WMA

0

100,000

200,000

300,000

400,000

500,000

600,000

June, 2011 July, 2011 August, 2011 September, 2011

Nut

rient

Loa

ds (l

bs/m

onth

)

Trend of Total Nutrient Loads to Willard Spur

Total Nitrogen

Total Phosphorus

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

June, 2011 July, 2011 August, 2011 September, 2011Tota

l Pho

spho

rus

Load

s (lb

s/m

onth

)

Trend of Phosphorus Loads to Willard Spur

BRMBR

Willard Bay

Willard/Perry WWTP

0

50,000

100,000

150,000

200,000

250,000

300,000

350,000

400,000

450,000

June, 2011 July, 2011 August, 2011 September, 2011Tota

l Nitr

ogen

Loa

ds (l

bs/m

onth

)

Trend of Nitrogen Loads to Willard Spur

BRMBR

Willard Bay

Willard/Perry WWTP

0.07%

10.35%

89.59%

0.00%

June, 2011 - Total Phosphorus Loads to Willard Spur

Willard Perry WWTP

Willard Bay

Bear River Refuge

Harold Crane WMA

0.16%

13.51%

86.33%

0.00%

June, 2011 - Total Nitrogen Loads to Willard Spur

Willard Perry WWTP

Willard Bay

Bear River Refuge

Harold Crane WMA

0.93%

0.71%

98.35%

0.00%

July, 2011 - Total Phosphorus Loads to Willard Spur

Willard Perry WWTP

Willard Bay

Bear River Refuge

Harold Crane WMA

1.42%

0.96%

97.63%

0.00%

July, 2011 - Total Nitrogen Loads to Willard Spur

Willard Perry WWTP

Willard Bay

Bear River Refuge

Harold Crane WMA

3.20%

0.50%

96.31%

0.00%

August, 2011 - Total Phosphorus Loads to Willard Spur

Willard Perry WWTP

Willard Bay

Bear River Refuge

Harold Crane WMA

2.78%

0.62%

96.60%

0.00%

August, 2011 - Total Nitrogen Loads to Willard Spur

Willard Perry WWTP

Willard Bay

Bear River Refuge

Harold Crane WMA