Applying SPOT Images to Study the Colorado River Effects on the Upper Gulf of California

Jesús A Aguilar-Maldonado,Eduardo Santamaría-Del-Ángel,María-Teresa Sebastiá-Frasquet

doi:10.3390/ecws-2-04951

Jesús A Aguilar-Maldonado, Eduardo Santamaría-Del-Ángel + Show 1 more

Open Access

https://doi.org/10.3390/ecws-2-04951

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Abstract

Sediment discharges from rivers play a key role in downstream ecosystems, both for ecosystem morphology (e.g., deltas) and productivity. However, the construction of dams and river regulation dramatically alter sediment transport. Currently, the Colorado River delta is one of the most transformed deltas in the world and, most years, no flow reaches the Gulf of California. In this study, we used satellite images for the observation and measurement of coastal water turbidity in the Upper Gulf of California (UGC) and Colorado River Delta (CRD). Specifically, we used the Earth-observing Satellites (in French Satellites Pour l’Observation de la Terre, SPOT) high spatial resolution satellite. We processed images of the wavelength 2 (S2610-680) from the period between 2008 and 2013 in the Biosphere Reserve area. Results showed that suspended material and high turbidity predominate in the CRD and intertidal zones of the UGC. High and very high turbidity values were due to two opposite coastal transport components along the Sonora and Baja California coasts. The high spatial resolution of the SPOT sensor effectively allowed the sediment transport gradients and the accumulation zones to be located in a highly variable area. This information provided by SPOT images can be very valuable for management decisions such as the amount of ecological flow that needs to be released. This area is the habitat of endangered species, such as totoaba (Totoaba macdonaldi) and vaquita (Phocoena sinus), that are seriously affected by the loss of estuarine conditions. High resolution satellite images can help to quantify the true extent of corrective measures.

Highlights

Regulation of large rivers through dams and diversion projects has caused dramatic changes to many delta ecosystems and receiving waters [1]
The Upper Gulf of California (UGC) is a highly productive marine area [4,5] that maintains its productivity despite the lack of river discharge
A total of 73 SPOT images of the period between 2008 and 2013 were processed. These images were classified according to oceanic conditions at the moment of the scene, in order to be able to study the turbidity in different conditions

Summary

Introduction

Regulation of large rivers through dams and diversion projects has caused dramatic changes to many delta ecosystems and receiving waters [1]. The Upper Gulf of California (UGC) is a highly productive marine area [4,5] that maintains its productivity despite the lack of river discharge. Despite some disagreement on how the river discharge contributes to this high productivity [7,8], there are several studies that link Colorado. River flow and UGC productivity [7,9] This area has several environmental protection figures, such as the Biosphere Reserve of the Upper Gulf of California and Colorado River Delta. It is the habitat of some endangered endemic species, such as the totoaba (Totoaba macdonaldi) and the vaquita marina (Phocoena sinus), which are estuarine-dependent [10]. This can supply additional information to managers making decisions regarding water allocation

Study Area

Image Processing

Results and Discussion