Using integrated terrestrial-marine monitoring to assess

restoration actionsCoral Bay, USVI

Julia Royster9th National Summit on Coastal and Estuarine Restoration and Management

December 12, 2018

St. John, USVI

U.S. Department of Commerce | National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 2

Coral Bay

Virgin Islands

National Park

Lameshur

Bay

Fish Bay Island Area: 50.8 km²

Population: 4,170

3

Threat: Sedimentation

4

Healthy Reef

Sediment-laden reef

Impact: Sedimentation

Sediment Transport: Watershed→Shore→Reef

Rain (minutes-days)

Erosion and watershed runoff (minutes-days)

Sediment plumes (minutes-days)

Deposition

Turbidity

RemovalResuspension

Carbonates& Organics

CONSIDERATIONS:

• Connectivity

• Scale

U.S. Department of Commerce | National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 6

Restoration Goal: Reduce Road Runoff

Kings Hill: Sediment Detention Pond

Lower Bourdeaux Route

107/108 Intersection:

Culvert Repair

Sugarbird Hill: Roadside swale

leading to existing cross-road swale

Calabash Boom: Step Pools

Calabash Boom: Road Paving

Johnny Horn Trail: Raingarden

Gerda marsh: Open Trench

Waterbar Construction

74 BMPs Implemented

7

ARRA Restoration

Projects in Coral Bay

Integrated Monitoring Goals

1) Evaluate how restoration actions affect generation

and delivery of runoff from terrestrial systems to

coastal waters

2) Gain a greater understanding of the linkages

between watershed processes and marine

sedimentation

3) Compare sediment-monitoring protocols

4) Evaluate effectiveness of restoration activities on

marine sedimentation and coral stress (indirectly)

U.S. Department of Commerce | National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 8

Terrestrial Monitoring

Sites

Marine Monitoring Sites

How did we do it? Dedicated collaborative partners

Dedicated funding

Measure over space & time

Terrestrial Data Collection

• 1 time test

• 20 unpaved road tests

• 18 tests of undisturbed soils

adjacent to roads

• 67 Coral Bay & 3 Lameshur Bay

• Checked 2013-2015 - every 13 days

• Simple & inexpensive

• Measure maximum depth of flow

Peak Crest Gauge

Guelph Permeameter

Marine Data Collection

• Collects:

• Sediment

• Lower temporal resolution

• Captures long-term relative

changes (not events)

• Works most of the time

• Collects sediments for

compositional and isotope

analysis

• Collects:

• Deposition

• Turbidity

• Current & Swell data

• High temporal resolution

• Captures short lived events

• Instrument failures & problems

• Requires high tech support and data

analysis

Lameshur Bay: 3 shore: 1 reef

Coral Bay: 3 shore, 2 reef 12 sites – 7 rainy seasons

Sediment Trap Nephelometer

Marine Data Collection

• Collects:

• Sediment (what metrics did you analyze

from the sediment collected?)

• ~ 25mL of sediment scraped from upper 2cm

seafloor adjacent to sediment traps.

• Every 26 days.

• Informs evaluation of sediment resuspension in

the sediment traps.

• Collects sediment: composition and texture.

• Collects:

• Net Sediment Accumulation

• 3 sites, collected every 26 days

• Data not conclusive – not useful

Benthic SampleSedPod

Marine Laboratory Methods• Sediment Trap Accumulation Rate

– Filtered, rinsed, dried, and weighed

– Mass per volume per day (mg cm-2 d-1)

• Sediment Composition (%T, %O, %C)

– Loss on Ignition (Determines percent organic,

carbonate, terrigenous [siliceous])

• Procedure of successive burns at 550°C

and 950 °C (Heiri et al. 2001)

• Sediment Texture (% clay, mean gs, etc.)

– LS200 Laser Particle Sorter

• Short-lived Radioisotope (SLR) activity

(2015-16)

– 7Be analyses (half life 53 days)

– G. Brooks & B. Larson, Eckerd College

Restoration Goal Results: Runoff Reduced!

• Model STJ-EROS2: Estimated decrease in

sediment delivery rate by 74%.

U.S. Department of Commerce | National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 14

Unpaved Roads:

91% decrease

Paved Roads:

9% decrease

Monitoring Results: Restoration Reduced Runoff

• Most effective at watershed scale

oKingshill Retention Pond: retained 42-46 Mg/year

• Effective for road segment, not watershed scale

o Road Paving: 4-29% erosion reduction

• Restored areas reduced sediment, but they did not

mimic runoff in undisturbed areas.

U.S. Department of Commerce | National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 15

Monitoring Results: Watershed and Marine Linkages

12/2/09 vs. 12/7/13 (~255 mm/pd)

% Change

TC-1B TC-3B TC-5 TC-8

Δ % Clay -21 -2 -27 -15

Δ % Ti -31 -16 -1 -1

Δ TAR 1246 121 -11 -38

% Change TC-1B TC-3B TC-5 TC-8

Δ % Clay -48 -49 -48 -44

Δ % Ti -36 -7 -3 -12

Δ TAR 1732 226 16 -56

12/2/10 vs. 10/11/11 (~165 mm/pd)

Approach:

Compare sampling periods of equivalent

rainfall /storm characteristics

Outcome (Trap & Benthic):

For periods with large storms:

Post-restoration decrease (up to 49%) in

clay and %Terrigenous (up to 36%)

Terrigenous Accumlation Rate variable

Reducing clay improves

water quality!

Clay is the best tracer of

restoration effectiveness!Comparison of equivalent storm rainfall

Results: Compare Sediment Monitoring Protocols

• Lower temporal resolution

• Captures long-term changes

• Works most of the time

• Collects sediments for

compositional and isotope

analysis

• High temporal resolution

• Captures short lived events

• Instrument failures & problems

• Requires high tech support and data

analysis

Accumulation rates: significantly correlated at

the majority of sites.

Lameshur Bay: 3 shore: 1 reef

Coral Bay: 3 shore, 2 reef 12 sites – 7 rainy seasons

Recommendation: Sediment traps and benthic sediment monitoring of sediment texture and composition

over multiples seasons most cost-effective at detecting changes related to restoration activities.

Results: Impact of Restoration on Reef Sedimentation

• Resuspension of terrigenous sediment delays water quality improvements until advection or burial takes place.

o Less clay = shorter-lived turbidity plumes from resuspension.

• Coral stress (indirectly) – difficult to measure, other studies suggest minimizing total terrigenoussediment and silt are keys to reducing coral stress.

U.S. Department of Commerce | National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 18

For Managers

• It is unrealistic to expect restoration actions to reduce road runoff to 0.

• Dr. Ramos-Scharrόn developed a simple method to predict whether a road runoff diversion structure can prevent delivery of runoff into the bay.

• Effectiveness metrics at the restoration or management action site are the most simple and cost-effective.

• In-water percent clay is the best tracer of restoration effectiveness.

• Simultaneous collection of both terrestrial and marine data allow for controlling some of the independent factors that can affect marine water quality and sedimentation samples.

U.S. Department of Commerce | National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 19

Lessons Learned

• Not all restoration actions effectively reduce watershed erosion and sediment yields.

• Land-based sediment transport is COMPLEX!

• Long-term monitoring is required to separate natural variability from changes in runoff due to management actions.

• Baseline studies to understand the nature, pathways, and timescales of connectivity between watershed and coral reefs are critical to implement site-specific monitoring.

• Multi-disciplinary teams are ESSENTIAL!

U.S. Department of Commerce | National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 20

Partners

Funding Sources:NOAA Coral Reef Conservation Program

NOAA ARRA

National Fish and Wildlife Foundation

University of Puerto Rico Sea Grant

• University of Texas – Austin • Dr. Carlos Ramos-Scharrόn

• University of San Diego • Dr. Sarah Gray

• Coral Bay Community CouncilSharon Coldren

• NOAALiz FaireyLisa VandiverDaphne Boothe

• VI RC & DMarcia Taylor

• VI Field Assistants• Matt Rasmussen, Bruce

Swanson, Prof. Matt LaFevor and others

• The Geezer Sailing and Snorkeling Society

Phil StrengerRoy Proctor

• VI Environmental Resource Station

• VI National Park

• VI DPNR/DEP

Geezer motto: “Measure twice…don’t forget to cut”

Thank youJulia Royster, julia.royster@noaa.gov

Dr. Carlos Ramos-Scharrόn, cramos@austin.utexas.edu

Dr. Sarah Gray, sgray@sandiego.edu

Coral Stress

• USVI 2013

impact

• Accumulation

rates

• Siltation > 4

mg/cm2/d

• Terrigenous >

10 mg/cm2/d

U.S. Department of Commerce | National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 23

Total

Ble

ac

hin

g P

reva

len

ce

0.0

0.2

0.4

0.6

0.8

1.0Silt/Clay Terrigenous

Old

Mo

rta

lity

Pre

va

len

ce

0.0

0.2

0.4

0.6

0.8

1.0

Flux (mg/cm2/day)

0 10 20 30 40 50 60 70

Imp

air

me

nt

Pre

va

len

ce

0.0

0.2

0.4

0.6

0.8

1.0

Flux (mg/cm2/day)

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

R2 = 0.285 R2 = 0.682* R2 = 0.807*

R2 = 0.231 R2 = 0.675*

R2 = 0.431 R2 = 0.668*

R2 = 0.736*

Flux (mg/cm2/day)

0 2 4 6 8 10

R2 = 0.625

Marine sediment monitoring field methods

Sediment traps (up to 17 sites; ~26 day resolution)

July-Dec from 2007/8-2016)

Tubes: 2 X 8

inches

(consistent

collection

between tubes)

2.2in

Benthic samples• ~25mL; upper 2 cm of the

benthic substrate

60 cm