The Control of Saltwater Intrusion into Laguna de Bay: Socioeconomic and Ecological Significance

Santos-Borja, Adelina C.

doi:10.1080/07438149409354192

Cited by 12 publications

(12 citation statements)

References 2 publications

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“…The water flows from the lake toward Manila Bay through the Pasig River, which is known as the only outlet of the lake. By contrast, at certain periods of high tide in Manila Bay and low water level in the lake, which frequently occur during the dry season, the Pasig River reverses its flow direction, bringing saline water from Manila Bay and polluted water from industrial and domestic effluents to the lake [24]. Therefore, the lake exhibits a marked inter-lake variation in trophic states.…”

Section: A Study Areamentioning

confidence: 99%

Multi-task Convolution Neural Network for Season-Insensitive Chlorophyll-A Estimation in Inland Water

Nguyen

Lin

Syariz

et al. 2021

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

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Chlorophyll-a (Chl-a) concentration, a crucial indicator of phytoplankton biomass, is sensitive to seasonality. The variations in trophic states regarding seasonality and the changes of spectral properties of water bodies pose uncertainties to the accuracy of remote sensing semi-empirical models. In particular, lakes in subtropical regions generally experience different trophic states in dry and wet seasons. In this study, a season-insensitive Chl-a retrieval model using multi-task convolution neural network with multiple output layers (MCNN) is proposed. A layersharing network combined with data augmentation is adopted to alleviate the issue of insufficient quantity of in situ samples. In addition, a hyperparameter optimization is performed to automatically refine the MCNN architecture. To evaluate the accuracy of proposed method, Laguna Lake, one of the largest lakes in Southeast Asia, is selected as the validation target. The lake is characterized by oligotrophic and mesotrophic states in wet season, whereas the states change to mesotrophic and lowlevel eutrophic states in dry season. A collection of Sentinel-3 Ocean and Land Colour Instrument Level-2 images and 409 in situ samples with the Chl-a concentration range 1.24-22.30 mg m −3 were used for model calibration and evaluation. Experimental results showed that MCNN with the performance of average R 2 =0.74, RMSE=2.06 mg m −3 , Pearson's r=0.86 outperforms related semi-empirical models including normalized difference chlorophyll index, two-band and three-band models, and WaterNet. The Chl-a prediction accuracy was improved by 7.19-14.6%, in terms of RMSE, compared with WaterNet.

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Section: A Study Areamentioning

confidence: 99%

Multi-task Convolution Neural Network for Season-Insensitive Chlorophyll-A Estimation in Inland Water

Nguyen

Lin

Syariz

et al. 2021

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

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“…Experts emphasized the importance of controlling this flux as it would enable other uses of the lake for urban domestic water supply and irrigation through decreased salinity and nutrient load. However, drawing from experiential knowledges of lake ecology, lake producers opposed the NHCS as it limited the vital saline flux that seasonally revives the fisheries (Santos-Borja, 1994).…”

Section: Resisting Infrastructure and Living In A Non-city Hazardscapementioning

confidence: 99%

Producing an urban hazardscape beyond the city

Saguin

2017

Environ Plan A

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Urban socioecological risk, like other urban metabolic processes, embodies relations between the city and the non-city. In this paper, I trace the production of urban risk within and beyond the city through the lens of the hazardscape using the case of Metro Manila and Laguna Lake in the Philippines. Building on recent interventions in urban political ecology that seek to map the terrains of extending urban frontiers, I examine the processes that construct city and non-city spaces in urbanization through flood control. I synthesize narratives of the material-discursive production of risk mediated by infrastructure with histories of landscape and livelihood change in an urban socioecological frontier to make two related arguments. First, discursive constructions of city and non-city and the material flows that connect them shape the production of urban ecological risk, with material consequences for non-city vulnerabilities. Second, infrastructure plays an important mediating role in the production of hazardscapes. The intersection of flows of water, discursive urban imaginaries in state plans, and livelihoods in Metro Manila and Laguna Lake exemplifies metabolic relations that reveal the spatio-temporal connections of cities with landscapes that make their functioning possible.

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“…Occurring during the dry months when the water level begins to fall below sea level, the circulating saltwater helps to clear the turbid lake, thereby improving photosynthetic activity and increasing primary productivity. This is usually followed by increased abundance of phytoplankton and zooplankton in the lake, which then improves fish growth by providing food and reducing pathogenic microorganisms (Palisoc ; Santiago ; Santos‐Borja ). Saltwater intrusion is able to speed up production time and allows a faster turnover whenever two or three crop cycles in a year becomes possible.…”

Section: Confronting and Appropriating Nature In Productionmentioning

confidence: 99%

“…Pen operators and fisherfolk organizations joined together to protest against the operation of the hydraulic control structure, which they believed prevented the intrusion of saltwater that was vital to the productivity of the lake fisheries. Their actions influenced state administrators to open the gates indefinitely in 1985, only 2 years after they started operating and 7 years after initial construction (Santos‐Borja ). Despite the structure remaining open to allow the flow of water from the river to the lake, producers still experience years without saltwater intrusion.…”

Section: Confronting and Appropriating Nature In Productionmentioning

confidence: 99%

Blue Revolution in a Commodity Frontier: Ecologies of Aquaculture and Agrarian Change in Laguna Lake,Philippines

Saguin

2015

Journal of Agrarian Change

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The Control of Saltwater Intrusion into Laguna de Bay: Socioeconomic and Ecological Significance

Cited by 12 publications

References 2 publications

Multi-task Convolution Neural Network for Season-Insensitive Chlorophyll-A Estimation in Inland Water

Multi-task Convolution Neural Network for Season-Insensitive Chlorophyll-A Estimation in Inland Water

Producing an urban hazardscape beyond the city

Blue Revolution in a Commodity Frontier: Ecologies of Aquaculture and Agrarian Change in Laguna Lake,Philippines

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