Hydrology

PUERTO RICO WATER QUALITY STANDARDS REGULATION, AS AMENDED, ON MARCH 2003

Abstract: 
The Environmental Quality Board recognizes that water pollution is detrimental to public health and welfare, creates public nuisances, is harmful to wildlife, fish and other aquatic life, and impairs domestic, agricultural, industrial, recreational and other beneficial uses of water. It is the goal of this Board, and this Regulation, to preserve, maintain and enhance the quality of the waters of Puerto Rico in such manner that they be compatible with the social and economic needs of the Commonwealth of Puerto Rico. The purposes of this Regulation are to: (1) designate the uses for which the quality of the waters of Puerto Rico shall be maintained and protected, (2) prescribe the water quality standards required to sustain the designated uses, (3) identify other rules and regulations applicable to sources of pollution that may affect the quality of waters subject to this Regulation and (4) prescribe additional measures necessary for implementing, achieving and maintaining the prescribed water quality. This Regulation is enacted in accordance with Law No. 9 approved on June 18, 1970, as amended known as the Public Policy Environmental Act, and nullifies any previous provision, resolution, agreement or regulation of the Commonwealth of Puerto Rico on the same subject which may contradict this Regulation.

Hydrologic Modeling of Land Processes in Puerto Rico Using Remotely Sensed Data

Hydrologic Modeling of Land Processes in Puerto Rico Using Remotely Sensed Data
Cruise, J. F.; Miller, R. L.
Journal of the American Water Resources Association, vol. 30, Issue 3, p.419-428

Abstract: 
An integrated, multi-disciplinary effort to model land processes affecting Mayaguez Bay in western Puerto Rico is described. A modeling strategy was developed to take advantage of remotely sensed data. The spatial, interannual, and seasonal variability of sediment discharges to the bay were also evaluated. Classified images of remotely sensed data revealed the spatial distribution and quantities of land use classes in the region and aided in the discretization of the watershed into homogeneous regions. These regions were modeled using a geomorphic modeling technique based upon spatially averaged parameters. Simulation results from the modeling effort compared favorably with observations at two locations within the watershed. Results showed that runoff and sediment loads from the area exhibit a marked seasonal trend and that deforested areas located in the foothill regions of the watershed contribute a disproportionate share of the sediment load to the bay. In years when rainfall distributions are uniformly distributed over the area, the sediment yields may be up to 100 percent higher than years when the rainfall is concentrated in the heavily forested mountainous regions.

Harmonic and Simple Kriging Analyses of Diurnal Precipitation Patterns in Puerto Rico

Sen-Roy S, Balling JrRV:
"Harmonic and Simple Kriging Analyses of Diurnal Precipitation Patterns in Puerto Rico",
Caribbean Journal of Science 41 (2) : 181-188 (Aug 2005)

Abstract: 
ABSTRACT.—Relatively large, topographically complex tropical islands can produce diurnal precipitation patterns that vary considerably over relatively short distances. In this investigation, we assembled a variety of databases to analyze diurnal rainfall patterns in Puerto Rico. We found strong diurnal cycles for all parts of the island with times of maximum frequency or total that ranged from pre-dawn in the east to midafternoon in the west. The pattern is similar to findings from Hawaii, and appears related to the daily pattern of katabatic and anabatic winds interaction with the predominant easterly trade winds. The diurnal pattern in rainfall was consistent through the year and not significantly affected by local sea-surface temperatures, El Niño-Southern Oscillation, and/or the North Atlantic Oscillation.

MINIMUM INSTREAM FLOW ESTIMATION AT UNGAGED STREAM SITES IN PUERTO RICO

Abstract: 
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.

Convective rainfall regions in puerto rico

Carter, M.M., 1995. Convective Rainfall Regions in Puerto Rico.
Masters thesis, Florida State University, Tallahassee, 75pp.

Abstract: 
Geographical regions of covariability in hourly precipitation over the island of Puerto Rico are exposed using factor analysis. It is argued that the data are consistent with a common factor model when an orthgonal rotation is applied to the factor loading matrix. The results suggest that Puerto Rico can be divided into six regions, with each region having a similar covariance structure of summer season convective rainfall. The six regions can be grouped into a western area and an eastern area based on contrasting diurnal rainfall signatures. The study is the first step in developing improved forecast guidance for precipitation over the island. It is believed to be one of the first studies attempting geographical regionalization of precipitation on the convective scale.

From theory to practice: building more resilient communities in flood-prone areas

López-Marrero T, Tschakert P (2011). ‘From
theory to practice: building more resilient
communities in flood-prone areas’ Environment
and Urbanization 23 (1): in press.

Abstract: 
Enhancing community resilience is key to reducing vulnerability in the face of natural hazards. In this article we discuss the elements that support or undermine community resilience to floods and propose ways of enhancing it. In the study, participatory methods and techniques were used with community members and emergency managers from a flood-prone municipality of Puerto Rico, including conceptual mapping, participatory mapping, and listing and ranking. The findings suggest that enhancing resilience in these communities requires: support for social learning by building on existing knowledge; stressing the importance of developing a diverse set of flood management options; and promoting effective linkages and collaborations between community members and emergency managers to encourage collective flood management. For this to happen, however, mutual distrust, lack of confidence and other obstacles must be overcome.

An integrative approach to study and promote natural hazards adaptive capacity: a case studyof two flood-prone communities in Puerto Rico

LÓPEZ-MARRERO, T. (2010), An integrative approach to study and promote natural hazards adaptive capacity: a case study of two flood-prone communities in Puerto Rico. The Geographical Journal, 176: 150–163. doi: 10.1111/j.1475-4959.2010.00353.x

Abstract: 
capacity to natural hazards of exposed populations. This paper analyses the strategies of adjustment implemented by members of two flood-prone communities in Puerto Rico, and discusses how the adoption of these strategies and other factors could influence future adaptive capacity and vulnerability to floods. Semi-structured interviews with community members from different resource endowment groups were used to elicit the resources behind the process of adjustment along with additional factors that could influence future adaptive capacity, including their perceptions of risks related to floods. The analysis revealed how access to resources – including material, economic and human resources – has facilitated living with floods in these communities; although not everyone has been able to adapt in the same way. Past actions, along with public responses being undertaken in the area (i.e. flood control project and upstream structural modifications) appear to be reducing flood-risk perceptions and promoting a false sense of security among community members, irrespective of resource endowment group. For that reason, developing ways to increase awareness about future flood potential and making clear the need for complementary non-structural strategies is imperative. In short, the research findings emphasise that access to resources and cognitive factors are important determinants of adaptive capacity. Hence, both should be taken into account while developing practical strategies towards increasing adaptive capacity and reducing vulnerability to floods specifically, and to other natural hazards in general.

Putting adaptive capacity into the context of people’s lives: a case study of two flood-prone communities in Puerto Rico

López-Marrero, T. and B. Yarnal (2010). Putting adaptive capacity into the context of people's
lives: a case study of two flood-prone communities in Puerto Rico. Natural Hazards 52:
277-297.

Abstract: 
Recent developments in the vulnerability literature have contested the use of technical solutions as the sole adaptive strategies to reduce natural hazard impact; this literature emphasizes the need to attend to the wider everyday risks to which people are exposed and that aggravate hazard vulnerability. Using a case study of two flood-prone communities in Puerto Rico, this article supports and enhances that literature by placing floods within a wider context of other risks and determining how everyday risks influence people’s perceptions of and capacity to adapt to floods. Participatory methods are used to elicit the everyday risks that concern community members. The analysis reveals that participants perceive floods as one of their risks, but they see them as neither the most important nor most severe risk in their lives. Instead, they find other concerns—health conditions, family well-being, economic factors, and land tenure—more pressing. These competing risks limit adaptive capacity and increase vulnerability to natural hazards. The results suggest that addressing these multiple risks, mainstreaming flood management and adaptation into the wider context of people’s general well being, and increasing risk perception will strengthen adaptive capacity to present and future floods.

Tropical cyclones and the flood hydrology of Puerto Rico

Smith, J. A., P. Sturdevant-Rees, M. L. Baeck, and M. C. Larsen (2005), Tropical cyclones and the flood hydrology of
Puerto Rico, Water Resour. Res., 41, W06020, doi:10.1029/2004WR003530.

Abstract: 
Some of the largest unit discharge flood peaks in the stream gaging records of the U.S. Geological Survey (USGS) have occurred in Puerto Rico. Many of these flood peaks are associated with tropical cyclones. Hurricane Georges, which passed directly over the island on 21–22 September 1998, produced record flood peaks at numerous USGS stations in Puerto Rico. The hydrology and hydrometeorology of extreme flood response in Puerto Rico are examined through analyses of rainfall, based on Weather Surveillance Radar–1988 Doppler (WSR-88D) radar reflectivity observations and USGS rain gage observations and discharge from USGS stream gaging stations. Peak rainfall accumulations of more than 700 mm occurred in the central mountain region of the island. The largest unit discharge flood peaks, however, were located in the eastern portion of the island in areas with smaller storm total rainfall accumulations but markedly larger rainfall rates at 5–60 min timescale. Orographic precipitation mechanisms played an important role in rainfall distribution over the island of Puerto Rico. Amplification of rainfall accumulations was associated with areas of upslope motion. Elevated low-level cloud water content in regions of upslope motion played an important role in the maximum rainfall accumulations in the central mountain region of Puerto Rico. The largest unit discharge flood peaks, however, were produced by a decaying eye wall mesovortex, which resulted in a 30–45 min period of extreme rainfall rates over the eastern portion of the island. This storm element was responsible for the record flood peak of the Rı´o Grande de Lo´iza. The role of terrain in development and evolution of the eye wall mesovortex is unclear but is of fundamental importance for assessing extreme flood response from the storm. Hydrologic response is examined through analyses of rainfall and discharge from five pairs of drainage basins, extending from east to west over the island. These analyses point to the importance of short-term rainfall rates for extreme flood response. The hydrologic response of Puerto Rico is compared with two other extreme flood environments, the central Appalachians and Edwards Plateau of Texas. These analyses suggest that the high rainfall environment of Puerto Rico is linked to the development of a hydraulically efficient drainage system.

GROUND WATER OPERATIONAL MODEL YAUCO, PUERTO RICO

Abstract: 
A numerical groundwater model was constructed to simulate groundwater flow in the Yauco Alluvial Valley aquifer. The groundwater flow model was constructed to evaluate future management options, including the potential to increase aquifer firm yield through a conjunctive management of ground and surface water. The aquifer within the Yauco Valley consists of river alluvium deposited over the incised Juana Díaz formation and Ponce limestone. A finite-difference, numerical model was developed to simulate ground water flow in the Yauco Valley. The single-layer model encompasses the entire alluvial deposits of the valley which extends from the Yauco town to the Caribbean Sea. The model was calibrated to October 1960 and 1970 to 1974 water levels. Different management scenarios were modeled to analyze and determine how much water can be extracted from the aquifer and evaluate the conjunctive use potential. Results demonstrate that the aquifer could be subjected to a total extraction in the order of 4.6 to 4.8 mgd (1-1.25 mgd above current extractions) without reducing the water levels to a point that could produce saltwater intrusion. Simulations showed that groundwater extractions could be increased by 5 mgd to 6 mgd during the dry season (March-August) if artificial recharge is provided in the range of 1.3 mgd to 1.95 mgd on a year-around basis. This demonstrates that the potential exists to conjunctively use ground and surface water to increase aquifer yield
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