water supply

Integrated Water Plan for Puerto Rico, December 2006

"Plan Integral de Agua" December, 2006.

Water is a natural resource important for life, growth and development of cities and towns. It's "Not just the most basic of necessities it's also the basis of sustainable development." The spatial and temporal distributions varies in such a way that its in abudnant in some regions and times while is is vary limited in others. While it is considers a renewable resource it is no less correct that improper management can lead to a reduced quantity and quality of available water. It's also the case that contamination can also render the resource unusable. For these reasons the availability, quality, and management of water resources represents a grand challenge for Puerto Rico and most of the world. El agua es un recurso natural de vital importancia para la vida, crecimiento y desarrollo de los pueblos. Es “[n]o sólo la más básica de las necesidades, sino también el núcleo del desarrollo sostenible”1. Su distribución espacial y temporal varía de forma que, mientras es abundante en unas regiones o épocas, en otras es muy limitado. A pesar de que se considera un recurso renovable no es menos cierto que su manejo inapropiado, puede tener el efecto de reducir la cantidad disponible y utilizable del recurso. De igual forma, la contaminación irreversible del recurso puede convertirlo en uno agotable. Es por ello que la disponibilidad, calidad y manejo adecuado del recurso representa un gran desafío para Puerto Rico y la mayor parte del mundo.

Water resources of Puerto Rico

Wilson, H.M., 1899, Water resources of Puerto Rico, U.S. Geological Survey Water-Supply Paper 32


Minimum streamflow information is commonly used to determine the water available for extraction and to analyze instream environmental parameters. Minimum streamflow estimates are frequently desired at ungaged locations, either on a stream having gages at other locations, or a stream without any gages. This study presents regional regression equations to estimate minimum streamflow using two parameters: watershed area and mean annual rainfall. These equations are based on a revised rainfall map which incorporates the available rainfall data from 127 raingage stations and also considers geographic parameters.

Valuing water and sediment tradeoffs between forest and pasture in montane tropical environments in Puerto Rico

Gingold, E. A. (2007). Valuing water and sediment tradeoffs between forest and pasture in montane tropical environments in Puerto Rico. University of Pennsylvania Scholarly Commons. Retrieved 3/20/11 from http://repository.upenn.edu/cgi/viewcontent.cgi?article=1010&context=mes...

Effective land use policy must weigh both the private and public costs and benefits of converting forests to alternate land uses. This project assesses the private and public impacts of forest to pasture conversion in the montane regions of Puerto Rico. Due to the island's water supply problems, hydrologic ecosystem services were found to be the most significant resource impacted. The value of carbon sequestration lost through conversion was found to range from 9-36 $/ha/yr. The value of other ecosystem services, notably recreation and biodiversity, were found to be highly significant in certain localities but small on an average island-wide basis. The model created in this study found that the public costs of reservoir sedimentation resulting from increased erosion and the higher incidence of landslides on pastures outweigh the public benefits of increased runoff in areas where with slopes of approximately 21o and a Revised Universal Soil Loss Equation topographic factor greater than 6.5. Results were highly dependent on the amount of sediment that is transported from the pasture to the reservoir (e.g. the sediment delivery ratio) and the marginal value of water. The private returns to pasture (400 $/ha/yr) were generally found to be greater than the sum of the public costs. The results suggest that policy-makers should take local environmental variation into account when designing forest conservation strategies. Policies should target areas with high slopes and high sediment delivery ratios.

Instream-Flow Analysis for the Luquillo Experimental Forest, Puerto Rico: Methods and Analysis

Scatena, F.N.; Johnson, S.L. 2001. Instream-Flow Analysis for the Luquillo Experimental Forest, Puerto Rico: Methods and Analysis. Gen. Tech. Rep. IITF-GTR-11. Rio Piedras, PR: U.S. Department of Agriculture, Forest Service, International Institute of Tropical Forestry. 30 p.

This study develops two habitat-based approaches for evaluating instream-flow requirements within the Luquillo Experimental Forest in northeastern Puerto Rico. The analysis is restricted to instream-flow requirements in upland streams dominated by the common communities of freshwater decapods. In headwater streams, pool volume was the most consistent factor in predicting the abundance of common freshwater shrimp. In second- and third-order tributaries, both water depth and velocity can be used to define their habitats. The most common species of shrimp are reclusive during the day; at night they prefer areas of low velocity (<0.09 m/s) and areas shallower than 0.4 m. In headwater streams, total usable shrimp habitat declines rapidly when water depth in the deepest pools is less than 0.5 m. In second-and third-order tributaries, the amount of habitat declines rapidly when discharge is within one standard deviation of the average annual 7-day minimum flow. These dis-charges are typically exceeded between 95 and 99 percent of the time. Analysis of habitat loss associated with different instream-flow constraints showed that habitat loss increases greatly when water extraction is equal to or greater than Q98. Among-reach differences in the amount of usable habitat resulting from differences in channel morphology can be as high as 35 percent. Therefore, site-specific studies should be conducted when using habitat-preference relations in a particular area.
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