Chip Hunt U. S. Geological Survey, Honolulu, hi

— NOAA / USGS Cooperative Program — Simulation of Coastal Wastewater Injection in Hawaii using SUTRA … and the Value of Compelling Visualizations in Conveying Results to the Non-Specialist Public

• Chip Hunt

• U.S. Geological Survey, Honolulu, HI

• [e-mail]

Photo: Jennifer Smith

Objectives

• Estimate ground-water nutrient loads

• Identify useful wastewater tracers

• Answer injection-plume questions:

• Where does it go?
• “We inject this stuff, and if it gets to the coast …”
• - Plume width at coast?

3-D Ground-Water Model

• Code: SUTRA (Voss & Provost, 2002, USGS)

• Variable-density flow & solute transport

• Solute = Salt (freshwater-saltwater flow)

• DID NOT simulate nutrient transport

• Post-processing to visualize plume, GW age

• Kh= 3000 m/d Kh:Kv anisotropy=200:1

• aL = 76 m aT = .022 m

Model Mesh

Injection Plume is Buoyant

Salinity Visualization

Effluent-Tracer Visualization

Plume internal structure, 20% shells

Ground-Water Age at Water Table

Algal tissue 15N highest near plume

Nutrient load per kilometer coast (kg / day – km coast)

Attenuated* wastewater nutrient load (kg / day – km coast)

Urban Nutrient Load? Don’t know.

… rough work but somebody’s gotta do it

Funding by NOAA ECOHAB (Ecology and Oceanography of Harmful Algae Blooms)