Monitoring in the Ahupua‘a

Michael Tomlinson

Department of Oceanography

Mokupuni (large islands) of Hawaiʻi (Aliʻi Nui or Head Chief)

Kauaʻi

Niʻihau

Kahoʻolawe

Lānaʻi

Molokaʻi Maui

Hawaiʻi

Oʻahu

Moku of Oʻahu (Aliʻi ʻai moku)

Ahupuaʻa of the Kona Moku (Konohiki)

Waikīkī

“Typical” Ahupua‘a

Konohiki Oversees • Water • Forestry (timber,

clothing) • Agriculture (kalo loʻi,

breadfruit, etc.) • Onshore/Nearshore

Fisheries (including aquaculture)

• Offshore Fisheries

Another depiction of an ahupuaʻa (Kamehameha Schools, 1993)

Waikīkī ahupuaʻa then (~1865) . . .

Mānoa Valley from Waikīkī, Painting by Enoch Wood Perry, 1865

. . . and now!

Characterize water quality (WQ) in watershed

Study temporal and spatial variations in WQ

Determine effect of NPS pollutants on WQ

Quantify natural and NPS contributions during base-flow and storm conditions

Evaluate potential effects of NPS pollutants on nearshore biota

Determine trace element and total suspended sediment (TSS) loads to coastal ocean

UHM Watershed Study Objectives

UHM Quarterly (Q) & Continuous Monitoring (CM) Stations

Tomlinson & Pygmy Flowmeter

Quarterly Manual Sampling

CM Station WK (upper watershed)

CM Station KHS (lower watershed)

Extreme Event Monitoring – Storms

The good,

the bad, &

the really UGLY!

Turbidity as a Surrogate for Suspended Sediment

DGT Time-Integrating Sampler Study

Discrete Sampling Program

Manual quarterly sampling, usually base flow (4 years)

Automated storm sampling (4 years)

Streamflow & T, C, pH, DO & turbidity at 5-minute intervals (4 years)

Estuarine grab sampling & water quality measured in situ concurrently with DGTs (7 months)

DGT Study Design

Compare 7 months of DGT results with stream data from discrete base- & storm-flow samples collected over 4 years

Compare DGT results with data from weekly discrete samples collected concurrently with DGT retrievals over 7 months

Estuary

Lower Watershed

Upper Watershed

Components of a DGT Sampler ABS plastic outer sleeve & piston 0.45-µm, polysulfone membrane filter Polyacrylamide hydrogel (~95% water) Layer of Chelex-100® resin in hydrogel

DGT Deployment Schemes

Estuary

Streams

DGT-Grab Comparison - Stream

Expected DGT concentrations (dissolved → colloids, i.e., ~0.02 µm) to be lower than discrete samples (0.2-µm filters)

DGT vs. 0.2-µm Filter

DGT vs. Grab Sample Copper Mystery (So, what happened here? Manual sampling missed

something? Diel cycle in Cu?)

Pacific Islands Ocean Observing System

Water Quality Component Locations

HiOOS Water Quality Sensors

Storm Effects (March 2009)

AUV – Δ Salinity at 2 - 4 m

Note fresher water near shore as a result of the 13MAR09 storm

Mar-09 Storm–Long Lasting Effects

11-March-2011 Japan Tsunami

Hawaiian Islands

Japan Tsunami Water Quality Effects

Japan Tsunami Water Quality Effects

Comparing Storm & Tsunami Turbidity

All Clear?

All of this within the Waikīkī ahupuaʻa

Mahalo! Questions?

Michael Tomlinson UHM Oceanography, Flagstaff, AZ 86004

928-266-2236, mtomlins@hawaii.edu

For attending the 2014 AIPG & AHS National Conference!

Continuous Monitoring Challenges Many samples, disparate intervals Cellular transmission Biofouling Calibration & biological long-term drift Data review and quality control

Many Samples, Disparate Intervals Component

Interval (min)* №/Yr

NWS Precipitation 15 35,040 USGS Streamflow 15 35,040 NOS Tides 6 87,600 NOS Meteorology (wind, T, P) 6 87,600 HiOOS NS (P, T, S, chl, turb) 4 131,400 HiOOS WQBs (T, S, DO, chl, turb) 20 26,280 HiOOS KNO (waves, currents, scatter, T) 20 26,280 HiOOS AUV (bathy, T, S, chl, scatter, curr) ~0.001 ~57,500/hr Event Sampling (varies) varies varies * Statistical analysis may require uniform interval using GRAN, Aquarius®, etc.)

Cb = bulk solution concentration δ = DBL (diffusive boundary layer) thickness Δg = diffusive gel thickness (ideally ≥10 × δ)

How the DGT

Works

DGT Assumptions & Requirements

Diffusive boundary layer thickness δ (unknown) not significant relative to length of DGT diffusion path Δg

Diffusion coefficients of the aquo ions represent most of the species present

Biofouling is not interfering with diffusion process

Ionic strength >1 mM (~60 µS/cm) pH must be >5 and <10

Discrete Sample Processing

Step 1 Filtration (0.2 µm)

Step 2 Acidification

(quartz distilled HNO3)

Step 3 FIA (8-HOQ

resin)

Step 4 ICP-MS analysis

DGT Processing Step 1 - DGT disassembly

Step 2 - Removal of resin gel

Step 3 - Resin gel leaching (24 hr)

Step 4 - ICP-MS analysis of DGT leachate

Calculating Mean Concentration

where: Cw = mean metal concentration in water M = mass diffused into DGT Δg = diffusive hydrogel thickness + membrane filter thickness DT = diffusion coefficient at any temperature t = deployment (exposure) time A = area of DGT window

WQB Sensor Information

Sensor Res/Prec Accuracy Cost

SBE 16plus CTD $23,000

Temperature 0.0001 °C 0.005 °C

Conductivity 0.00005 S/m 0.0005 S/m

SBE43 & 63 DO – 2%

WET Labs FLNTU

Chlorophyll 0.01 µg/L –

Turbidity 0.01 NTU –

ISUS NO3 Sensor ±0.5 µM ±2 µM or 10% $34,000

STOR-X Telemetry $14,000

C6 Multisensor Platform* various various $17,000

* Equipped with chlorophyll, CDOM, OB/FWA, turbidity, phycoerythrin, & crude oil sensors; battery pack; and mechanical wiper (wish list).