1. Near-stream Recharge to Protect Baseflows in the Upper San Pedro River, Arizona, USA
Laurel J. Lacher, PhD, RG
October 17, 2013
ISMAR8 Conference
Beijing, China
Lacher Hydrological Consulting
photo credit: The Nature Conservancy

2. Acknowledgements The Nature Conservancy: Holly Richter Brooke Bushman
David Gann Dale Turner

4. San Pedro
River

5. Why is this little river so
important?
BIODIVERSITY
84 species of mammals
> 41 species of reptiles and amphibians
> 100 species of breeding birds
> 250 species of migratory birds
6 native fish species
San Pedro River Downstream of the Riverstone Tract (photo by D. Haddad, Arizona State University)
San Pedro River (Photo by Jeff Smith)

6. San Pedro River Arizona, United States Sonora, Mexico N
Babocomari River
Rio de Fresnos N 10
miles

8. cu-ft/s (cu-m/s) (-0.06 to -0.03) (-0.03 to -0.003) (-0.003 to 0.003)km
miles

9. PURPOSE OF STUDY:
To evaluate the potential for near-stream recharge to sustain or improve existing
baseflows in the San Pedro and Babocomari rivers over the next century.

10. RECHARGE RATE OPTIMIZATION

12. baseflows at or above 2003 levels for 100 years?
QUESTION:
How much recharge would it take at each site to maintain
baseflows at or above 2003 levels for 100 years?
3.7
3.1
2.5
1.9
1.2
0.6
AF/yr
MCM/yr

13. QUESTION: Can simultaneous recharge increase efficiency?
Water Savings
3,800 AF/yr
(4.7 MCM/yr)
Average water savings:
364 AF/yr (0.45 MCM/yr)

14. Optimized Simultaneous Recharge at Three Sites
Simulated Difference in Baseflow from 2003 Conditions
Optimized Simultaneous Recharge at Three Sites
cu-m/s
-0.04 to -0.03
-0.03 to -0.01
-0.01 to
to 0.003
0.003 to 0.01
0.01 to 0.03
0.03 to 0.04
0.04 to 0.06
0.06 to 0.07

15. Take-Home Points Targeted near-stream recharge can protect baseflows.
Simultaneous operation of sites improves efficiency.
Thank you!
Laurel Lacher

17. Cubic-meters (cu-m) 1.7E06 1.5E06 1.2E06 0.99E06 0.74E06 0.49E06

18. PREDICTIVE Pumping Recharge ET Baseflow Recharge (cu-m/yr) 7.4E07
PREDICTIVE
Pumping
Recharge (cu-m/yr)
Recharge ET
Baseflow

19. Streamflow Gaging Station
Simulated Drawdown – Primary Regional Aquifer
Contour interval = 5 m 20 15 10 5
Drawdown (m)
San Pedro River
Babocomari River
San Pedro River
Babocomari River
San Pedro River
Babocomari River
Palominas
Hereford
Sierra Vista
Palominas
Hereford
Sierra Vista
Palominas
Hereford
Sierra Vista
Streamflow Gaging Station
Mexico
United States N
UTM Latitude (m north)
[a] 2000
[b] 2050
[c] 2100
555250
556250
557250
558250
559250
Cananea
Cananea
Cananea
UTM Longitude (m east)