TIDAL DYNAMICS OF WATER QUALITY AND MATERIAL FLUX IN THE FUKIDO MANGROVE RIVER: DATA FROM THE LAST DECADE OF FIELD OBSERVATIONS

Fires are a natural phenomenon in the boreal forest, but their frequency is expected to increase over the coming century. Fires may affect water quality and invertebrates in lakes, but there have been few studies in the northern boreal forest to describe these impacts. We collected data on water quality, macrophytes, and invertebrates from 20 lakes in the Sahtú Settlement Area of the Northwest Territories. Nine lakes were affected by fires in their catchments 4-5 years before data collection, while eleven were not. Our results showed that few water quality variables were associated with fires. However, remote sensing and field observations suggested that macrophyte biomass was higher in lakes affected by burns and this variable was a significant predictor of invertebrate composition. Burn history was an important predictor of the richness and abundance of invertebrates, but natural variability in lake properties was more important for explaining differences among lakes. Our results suggest that a better understanding of the effects of wildfires might be gained by examining how post-fire changes in macrophytes affect other trophic levels.

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Field Observations and Analyses of Water Quality Characteristics in a Dense Aquaculture Area Adjacent to a Coral Reef in Bolinao, Philippines

PROCEEDINGS OF COASTAL ENGINEERING JSCE ◽

10.2208/proce1989.55.1426 ◽

2008 ◽

Vol 55 ◽

pp. 1426-1430 ◽

Cited By ~ 3

Author(s):

Kota ASHIKAWA ◽

Kazuo NADAOKA ◽

Eugene C. HERRERA ◽

Takahiro YAMAMOTO ◽

Cesar L. VILLANOY ◽

...

Keyword(s):

Water Quality ◽

Coral Reef ◽

Quality Characteristics ◽

Field Observations ◽

Aquaculture Area

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Source Water Apportionment of a River Network: Comparing Field Isotopes to Hydrodynamically Modeled Tracers

Water ◽

10.3390/w12041128 ◽

2020 ◽

Vol 12 (4) ◽

pp. 1128

Author(s):

Lily A. Tomkovic ◽

Edward S. Gross ◽

Bobby Nakamoto ◽

Marilyn L. Fogel ◽

Carson Jeffres

Keyword(s):

Water Quality ◽

Numerical Modeling ◽

Stable Isotope ◽

Tidal River ◽

Chemical Characteristics ◽

Source Water ◽

Field Observations ◽

Primary Control ◽

Water Fraction ◽

Flood Season

Tributary source water provenance is a primary control on water quality and ecological characteristics in branching tidal river systems. Source water provenance can be estimated both from field observations of chemical characteristics of water and from numerical modeling approaches. This paper highlights the strengths and shortcomings of two methods. One method uses stable isotope compositions of oxygen and hydrogen from water in field-collected samples to build a mixing model. The second method uses a calibrated hydrodynamic model with numerical tracers released from upstream reaches to estimate source-water fraction throughout the model domain. Both methods were applied to our study area in the eastern Sacramento–San Joaquin Delta, a freshwater tidal system which is dominated by fluvial processes during the flood season. In this paper, we show that both methods produce similar source water fraction values, implying the usefulness of both despite their shortcomings, and fortifying the use of hydrodynamic tracers to model transport in a natural system.

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INVESTIGATING THE EFFECTS OF RIVER DISCHARGES ON SUBMERGED AQUATIC VEGETATION USING UAV IMAGES AND GIS TECHNIQUES

ISPRS Annals of Photogrammetry Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-annals-v-5-2020-93-2020 ◽

2020 ◽

Vol V-5-2020 ◽

pp. 93-99 ◽

Cited By ~ 1

Author(s):

A. Tamondong ◽

T. Nakamura ◽

Y. Kobayashi ◽

M. Garcia ◽

K. Nadaoka

Keyword(s):

Water Quality ◽

Submerged Aquatic Vegetation ◽

Aquatic Vegetation ◽

Field Survey ◽

Survey Methods ◽

River Mouth ◽

Water Clarity ◽

Ease Of Use ◽

Percent Cover ◽

Field Observations

Abstract. One of the major factors controlling the distribution and abundance of marine submerged aquatic vegetation (SAV) is light availability. Reduced water clarity due to sediment loading from rivers greatly affects the health and coverage of seagrasses and seaweeds. Monitoring SAV using unmanned aerial vehicles (UAV) has been getting attention because of its cost-effectiveness and ease of use. In this research, a low-cost UAV was utilized to assess the impacts of river discharges on SAV in Busuanga Island, Philippines. Linear regression was performed to determine the effectivity and accuracy of UAV-based percent cover estimation compared to established field survey methods of monitoring SAV. Water quality was estimated in the study area by performing spatial interpolation methods of in situ measurement of turbidity, chlorophyll, temperature, salinity, and dissolved oxygen using a multi-parameter water quality sensor. Current velocity and tidal fluctuations were monitored using bottom-mounted sensors deployed near the river mouth and in seagrass and seaweed areas with relatively good water clarities. Four stations were surveyed using automated UAV missions which were flown simultaneously with field observations. Each station surveyed has varying distances from the river mouth. Results from the classification of the UAV data and field survey show that SAV is more abundant as the distance from the river mouth increases and the turbidity decreases. Classification overall accuracies of UAV orthophotos ranging from 87.91–93.41% were achieved using Maximum Likelihood (ML) Classification. Comparison of field-based and UAV-based survey of percent cover of seagrasses show an overestimation of 1.75 times from the UAV compared to field observations.

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