Project B:

Streamflow, 

Water Quality, and

Sediment Transport 

in the Colorado 

River Ecosystem
The USGS team

• David Topping, GCMRC

• Ron Griffiths, GCMRC

• Nick Voichick, GCMRC

• Tom Sabol, GCMRC

• Dave Dean, GCMRC

• Nancy Hornewer, AZ Water Science Center

• Jon Mason, AZ Water Science Center

• Brad Garner, AZ Water Science Center

• Dave Sibley, CIDA

• Megan Hines, CIDA
How do operations at Glen Canyon Dam affect flows, 

water quality, sediment transport, and sediment 

resources in the Colorado River Ecosystem?

• Development of new database and website with 

user-interactive tools for data visualization and 

downloading, and the construction of sand budgets

• Publication of 5 peer-reviewed interpretive papers 

and 18 USGS Water-data reports
All products promised in the 2013-14 

Biennial Work Plan were delivered

• 4-6 peer-reviewed journal articles and USGS 

reports promised....5 delivered

• Annual data reports for the 9 USGS gaging 

stations online

• Real-time posting of data from these stations

• Real-time to monthly posting of all data on 

NEW WEBSITE

• Monthly to bi-monthly updates of the massbalance sand budgets on NEW WEBSITE 
Monitoring project with some research

We collect, post, and analyze the following data at stations 

located through the Colorado River Ecosystem, including 

key tributaries...

• Stage

• Discharge

• Water temperature

• Salinity (specific conductance)

• Turbidity

• Dissolved Oxygen

• Suspended- and bed-sediment data

• Sediment loads (silt and clay loads and sand loads)

• User-interactive sand budgets in 6 reaches from Lees Ferry to Lake Mead

Virtually all other projects funded by the GCDAMP use 

these data!
The single most significant accomplishment was 

the completion of the 

new database and website.

http://www.gcmrc.gov/discharge_qw_sediment/ 

http://cida.usgs.gov/gcmrc/discharge_qw_sediment/ 

The user-interactive tools available at this 

website to visualize and operate on the data are 

unique in the world. 
Colorado River at Lees Ferry, AZ

 Water years 2013-2014

• Discharge

• Water temperature

• Dissolved oxygen

http://www.gcmrc.gov/discharge_qw_sediment/ 
Upper Marble Canyon

 sand budget

 July 1, 2014 to 

 January 5, 2015

This project collects 

and processes 

the data used to 

trigger HFEs

http://www.gcmrc.gov/discharge_qw_sediment/ 
We have made major improvements in quickly 

characterizing the sand loads of the Paria River 

To date, we have processed 202 of the 231 suspended-sediment samples collected

during August – September 2014

Calculated sand loads changed by ~33% between the September 29 flood and 

mid October

Calculated sand loads changed by ~5% between mid-October and the November HFE 

Voichick and Topping (2014)
July 2010 – June 2014 change in sand 

mass balance by reach (in million metric tons)

+0.5±0.8

0.0±0.5

-1.7±0.9

+1.2±1.5

+0.1±1.1

+8.7±0.4 Topping et al. (preliminary data, do not cite)
July 2010 – June 2014 change in sand 

thickness by reach (in cm)

+6±10

-43±23

+5±7

+1±6

0±5

Topping et al. (preliminary data, do not cite)
July 2012 – June 2014 change in sand 

mass balance by reach (in million metric tons)

+1.1±0.5

+0.3±0.4

+0.8±0.7

0.0±0.4

+3.0±0.1

+0.5±0.2

Topping et al. (preliminary data, do not cite)
July 2012 – June 2014 change in sand 

thickness by reach (in cm)

+14±6

+9±9

+4±3

0±3

+6±2

Topping et al. (preliminary data, do not cite)
2014 HFE....luck ran out

• Unfortunately, 1 of the 2 acoustic-Doppler profilers at the 

River Mile 30 station, and 2 of the 3 acoustic-Doppler 

profilers at the Grand Canyon gaging station broke 

immediately before or during the 2014 HFE.

• We will be developing new acoustic calibrations once we 

retrieve and process the suspended-sediment samples 

still in the canyon (this happens in early March).

• As a result, we will not have final verified sedimenttransport results and sand budgets until May-June 2015.
What can we say today?

Increases in the upstream sand supply generally 

lead to increases in sand concentration at any 

given discharge 

(Topping et al., Water Resources Research, 

2000a, 2000b, Journal of Sedimentary Geology, 

2007)
River mile 30 River mile 225

Rubin (preliminary data, do not cite)
Average peak-flow sand concentrations increased at the River 

mile 30 and 61 stations between the 2012 and 2013 HFEs, 

suggesting that both the Upper and Lower Marble Canyon 

reaches were gaining sand. 

River mile 30 River mile 61

2012 HFE (higher Q) 1,200 mg/L 1,200 mg/L

2013 HFE 2,200 mg/L 1,700 mg/L

2014 HFE Unknown until April 1,400 mg/L

These increases in sand concentration imply that bar building 

was more efficient during the 2013 HFE than during the 2012 

HFE, especially near river mile 30.

Results from 2014 HFE remain unclear, stay tuned until May-June 

2015 for final results at all stations.

Topping et al. (preliminary data, do not cite)