Incorporating urban infrastructure into biogeochemical assessment of urban tropical streams in Puerto Rico (original) (raw)
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Spatio-temporal variation in stream water chemistry in a tropical urban watershed
Ecology and Society, 2014
Urban activities and related infrastructure alter the natural patterns of stream physical and chemical conditions. According to the Urban Stream Syndrome, streams draining urban landscapes are characterized by high concentrations of nutrients and ions, and might have elevated water temperatures and variable oxygen concentrations. Here, we report temporal and spatial variability in stream physicochemistry in a highly urbanized watershed in Puerto Rico. The main objective of the study was to describe stream physicochemical characteristics and relate them to urban intensity, e.g., percent impervious surface cover, and watershed infrastructure, e.g., road and pipe densities. The Río Piedras Watershed in the San Juan Metropolitan Area, Puerto Rico, is one of the most urbanized regions on the island. The Río Piedras presented high solute concentrations that were related to watershed factors, such as percent impervious cover. Temporal variability in ion concentrations lacked seasonality, as did all other parameters measured except water temperature, which was lower during winter and highest during summer, as expected based on latitude. Spatially, stream physicochemistry was strongly related to watershed percent impervious cover and also to the density of urban infrastructure, e.g., roads, pipe, and building densities. Although the watershed is serviced by a sewage collection system, illegal discharges and leaky infrastructure are probably responsible for the elevated ion concentration found. Overall, the Río Piedras is an example of the response of a tropical urban watershed after major sewage inputs are removed, thus highlighting the importance of proper infrastructure maintenance and management of runoff to control ion concentrations in tropical streams.
PloS one
Global metrics of land cover and land use provide a fundamental basis to examine the spatial variability of human-induced impacts on freshwater ecosystems. However, microscale processes and site specific conditions related to bank vegetation, pollution sources, adjacent land use and water uses can have important influences on ecosystem conditions, in particular in smaller tributary rivers. Compared to larger order rivers, these low-order streams and rivers are more numerous, yet often under-monitored. The present study explored the relationship of nutrient concentrations in 150 streams in 57 hydrological basins in South, Central and North America (Buenos Aires, Curitiba, São Paulo, Rio de Janeiro, Mexico City and Vancouver) with macroscale information available from global datasets and microscale data acquired by trained citizen scientists. Average sub-basin phosphate (P-PO4) concentrations were found to be well correlated with sub-basin attributes on both macro and microscales, whi...
Journal of the North American Benthological Society, 2011
Urbanization is degrading stream ecosystems worldwide. Tropical island streams may respond to urbanization differently than temperate streams because of their overall climate differences, and they may respond differently than continental tropical urban streams because of their reduced biological diversity and short drainages. We characterized the physicochemistry, physical habitat, and macroinvertebrate assemblages of 16 stream tributaries in the Rio Piedras Watershed (San Juan, Puerto Rico). We also described landuse patterns upstream from each sampling site for the entire subwatershed and for riparian buffers of 5-and 100-m width. Urbanization had a negative effect on the physicochemical and biological condition of the Rio Piedras. Streams were distributed in ordination space along a strong physicochemical gradient that was related to concentrations of K + , Mg 2+ , dissolved O 2 (DO), and PO 4 32. Along this gradient, DO and Mg 2+ decreased and PO 4 32 and K + increased with higher % urban cover in the subwatershed. Macroinvertebrate assemblages also were related to urbanization, and more macroinvertebrate families and pollution-sensitive taxa were found at sites where physicochemistry reflected less urban cover. Family richness and pollution-sensitive taxa were positively associated with greater % forest cover in the 5-m riparian buffer zone, a result that supports the use of riparian buffers to ameliorate the effects of urbanization on stream biointegrity in the Rio Piedras. Our results are similar to findings in urban streams in temperate zones and in tropical continental streams. Therefore, despite island characteristics, tropical island stream physicochemistry and macroinvertebrate assemblages responded to urbanization in ways that are in general agreement with the predictions of the Urban Stream Syndrome.
Environmental monitoring and assessment, 2017
Freshwater resources are increasingly scarce due to human activities, and the understanding of water quality variations at different spatial and temporal scales is necessary for adequate management. Here, we analyze the hypotheses that (1) the presence of a wastewater treatment plant (WWTP) and (2) a polluted tributary that drains downstream from the WWTP change the spatial patterns of physicochemical variables (pH, turbidity, dissolved oxygen, and electrical conductivity) and nutrient concentrations (reactive soluble phosphorus, total phosphorus, nitrogen series, total nitrogen, and total dissolved carbon) along a mid-order river in SE Brazil and that these effects depend on rainfall regime. Six study sites were sampled along almost 4 years to evaluate the impacts of human activities, including sites upstream (1-3) and downstream (5-6) from the WWTP. The impacts were observed presenting an increasing trend from the source (site 1) towards Água Quente stream (site 4, the polluted tr...
Urban streams in Puerto Rico: what can we learn from the tropics
Journal of The North American Benthological Society, 2009
Urbanization is increasing rapidly in tropical regions. Information on the response of tropical streams to urbanization is critically needed, but this information is limited. Here we summarize our current understanding of urban stream ecosystems in Puerto Rico, a tropical island with a high level of industrialization and large urban areas. We focused on 16 tributaries of the Rio Piedras watershed, which drains the San Juan metropolitan area, and 16 tributaries of the Turabo watershed, a rapidly developing suburban area. Urban effects on nutrients and aquatic macroinvertebrates were similar to those described for other geographic regions. PO 4 , K, and Mg concentrations increased considerably with urbanization, PO 4 -P ranged from ,5 mg/L in streams draining forested watersheds to .500 mg/L in heavily urbanized streams. Macroinvertebrate assemblage composition changed to dominance by tolerant taxa (e.g., snails, Chironomidae) as the proportion of urban land increased in the subwatershed. In contrast, other factors did not follow expected responses to urbanization. Stream hydrology was equally flashy in streams draining forested and urbanized watersheds. Urban streams were commonly channelized, but in contrast to studies done elsewhere, channel incision was not greater in urban than in forested streams. Degree of urbanization was not related to the integrity of the fish assemblages. River connectivity seems to be more important than urbanization in determining fish assemblage composition in Puerto Rican streams because all native species are migratory (i.e., diadromous). Urbanization increased water temperature and microbial activity. Overall, urban streams in Puerto Rico presented some unexpected responses to urbanization that seem to be the result of its island or coastal characteristics. Examples from Puerto Rico provide information on how tropical streams might respond to the impacts of urbanization.
Environmental Monitoring and Assessment, 2020
Poor water quality in urban streams places at risk the health of urban residents and the integrity of urban environments, ultimately leading to the "urban stream syndrome." In response to growing concerns regarding urban streams in Uruguay, we evaluated the spatiotemporal variation in water quality parameters in two urban streams, the Ceibal and La Curtiembre streams, over 12-18 months. A proposal for an Urban Water Quality Index (UWQI) was developed based on national water quality standards for two stream classes to assess variability in overall stream condition over time. Both streams displayed extremely high levels of fecal coliform concentrations in mid-downstream sites and relatively high levels of total dissolved phosphorus and ammonia well above the national standards of 0.025 mg/L and 0.02 mg/L, respectively. Nitrate was consistently below the national maximum of 44.3 mg/L, calling to question the adequacy of this standard for designated uses. Over 40% of samples had oxygen levels below the national standard of 5 mg/L, and a dead zone (average 1.5 mg/L) was detected in the downstream reach of the La Curtiembre stream. Despite differences in land use and urban context, monthly observations of nutrients and coliforms indicated high levels of contamination in mid-downstream reaches, which could present a health risk for the populations in Paysandú and Salto. This study highlights the degradation of urban streams in two major cities in Uruguay and the need for a comparative diagnosis of stream condition as a basis for decision-making regarding urban development and water resources.
Energy, Ecology and Environment
Water demand, pollution, and climate change threaten water security in industrialized and urbanized regions worldwide, especially in developing countries. Investments in massive infrastructure have often not met the water needs of the population, requiring water resource managers to adopt new approaches, such as decentralized and regionalized management at the micro-basin scale. However, little is known about the impact of anthropogenic activities on the water quality and vulnerability of streams that cross urban areas and feed into the main rivers and reservoirs supplying cities and industrial regions. The main goals of this research were to evaluate the water quality, pollutant loads, and effect of untreated sewage discharges in streams of the Piracicaba river basin, in the municipality of Americana, Southeast Brazil. The water quality parameters evaluated were as follows: pH, dissolved oxygen, electrical conductivity, biochemical oxygen demand, inorganic phosphorus, total phosphorus, total nitrogen, real colour, turbidity, total dissolved solids, metals (Ba, Cr, Cu, Ni, Pb, Cd, and Zn), total coliforms, and Escherichia coli. Descriptive statistics and multivariate analyses were performed. The results revealed chemical and biological degradation of the water resources, and vulnerability of the urban streams due to the release of untreated sewage into these waterways. The findings indicate the need for an immediate implementation of policies to monitor and control discharges of industrial effluents into the sewage collection systems, as well as discharges of sewage into rainwater drainage systems, together with the maintenance of green spaces.