Presentation by Mark Stone (University of New Mexico) at the Delft3D User Days, during Delft Software Days 2016. Tuesday 1 November 2016, Delft.

1. Assessment of Hydrologic and
Geomorphic Alterations Using
Floodplain Connectivity Metrics
Mark Stone, PhD, PE
Colin Byrne
University of New Mexico
Ryan Morrison, PhD, PE
Colorado State University

2. Overarching Research Themes
(2) Resilience of Socio-Ecological Systems
(1) Hydro-Geo-Ecological Processes
Channel-Floodplain Interface
Interactions of Flow and Vegetation
Floodwave Attenuation
Fish Passage
Environmental Flow Assessments
Resilience to Natural Disasters
Floods – Wildfires – Earthquakes
Endangered Species
Recovery and Restoration

3. Vulnerability
Ecosystem Services
& System Resilience
Watershed and Floodplain Development &
Narrowly Focused Resource Management
Watershed and River Restoration &
Holistic Resource Management
As natural systems are degraded, ecosystem services are
diminished and system resilience is lost.
Floods, Droughts, Wildfires,
Loss of Biodiversity, etc.

6. Investigate the impacts of flow modifications,
historical channel and floodplain modifications, and
river restoration on channel/floodplain processes in
the Middle Rio Grande.
Study Objectives

7. cida.usgs.gov
Rio Grande Watershed

8. is through the practice of
environmental flows.

9. Cochiti Dam and Reservoir

10. (Richard et al. 2005)

11. -2.5 m
-3 m
-2 m
+5 m
+2 m
Massong et al. (2009)

12. Rio Grande streamflow above Cochiti Dam (Otowi Gauge)

13. Upstream of Cochiti
Downstream of Cochiti
Impacts of Cochiti on streamflow

14. 5 kilometers
Historical RG Floodplain
Modern RG Floodplain
Modified structure and
function of riparian vegetation
Interrupted energy and nutrient fluxes
Lost maintenance of geomorphic
processes and features
Lost dissipation of hydraulic
energy and momentum
Reduction in floodwave attenuation
Reduction in groundwater recharge
Modified hyporheic exchange and
bank storage
The Impacts

15. Rio Grande Silvery Minnow - Southwestern Willow Flycatcher - Yellow Billed Cuckoo
Legal Impacts -Three Federally Listed Endangered Species

16. Methods
Applied D-Flow FM
35 km reach – Albuquerque MRG
Multiple physical configurations
- historical
- modern
- “restored”
Multiple flood conditions
- stead state (e.g. 100-yr)
- multiple synthetic and gauged floods

17. D-Flow Model
• Unstructured mesh with a
resolution of around 5 to 10 m
• Lidar, maps, and survey data were
used to define the topography
• Simulations completed at the UNM
Center for Advanced Research
Computing using a Linux cluster
• Extensive benchmarking to
determine “optimal” number of
partitions

18. Spatial Rating Curves
Water depth
Velocity
Shear Stress
as a function of Q
for every grid point
100
1000
Discharge(cms)
Spatial Metrics

19. Streamflow
Inundation
DepthVelocity Hence we can build a time series of
hydraulic characteristics for each grid
point in the domain; run stats on each
point; and create maps of those stats.
Shear
Stress

20. D-Flow FM mesh element boundaries
Digitized boundary of interest
D-Flow FM observation point with temporal output data
MATLAB calculated boundary element with averaged depth-velocity information
Unit flux vectors used to calculate dynamic fluxes across boundaries
Boundary Flux Calculations
Hence, we can investigate spatial and temporally varying fluxes of mass,
momentum, and other constituents moving across the channel/floodplain
boundary.

21. Percentage of time inundated Percentage change in inundation
0.01
3
-100
0
Impacts of Cochiti Dam on Inundation Patterns

22. Hydrodynamics
Hydrology for
each scenario
Evidence
Time
DischargeBayesian Network Model for Riparian Recruitment
Site Condition
Morrison and Stone. 2014. Water Resources Research.

23. Decrease in Probability of
Riparian Recruitment

24. Mass Flux between the channel and floodplain

25. Cumulativemasstransferredtothefloodplains(kg/km)

26. 0 10 20 30 40 50 60 70 80 90 100
Time (hrs)
-4
-2
0
2
4
6
8
Masstransferacrossboundary(kg)
# 10
4
Right CH-FP
Left CH-FP
RS 1
RS 2
RS 3
RS 4
RS 5
RS 6
RS Total
Flood peak leaves reach
Simulated flood peak of 300 cms

27. Simulated flood peak of 300 cms

28. Reconstruction of Historical
Channel and Floodplain

29. Historical (1918) Condition
142 cms (5000 cfs)
Modern Conditions
36 km2 6 km2

30. Discussion and Conclusion
Historical channel, floodplain, and hydrologic modifications have
profoundly impacted floodplain processes in places like the Rio Grande.
The spatial assessments of inundation frequency, water fluxes, riparian
recruitment, and floodwave attenuation (etc.) provide insights into the
roles and significance of various stressors on ecosystem processes and
to identify methods to address their impacts.
The temporal assessments provide insights for comparing overall
impacts of streamflow and geomorphic modifications between sites or
scenarios over an extended period of time.
Boundary flux assessments provide greater insights into underlying
physical processes at the floodplain/channel interface.