Water Resources Council Research Articles

Revisiting Turcotte’s approach: flood frequency analysis

Flood frequency estimation forms the basis for engineering design of hydraulic structures, including bridges and culverts, local and regional development planning, and flood insurance. In the United States, the Water Resources Council recommends using the Log-Pearson Type III (LP3) distribution as a standard for use with the annual peak flow data. However, researchers have argued for the use of more than one streamflow value in a year thus increasing the sample size and decreasing the sampling error in the estimates of the flood quantiles. In this study, conducted over Iowa, the authors revisit the method proposed by Donald Turcotte and others to use power-law distribution applied to streamflow peak values for events separated by a time window. In contrast to those earlier studies, the authors applied formal statistical approach based on the maximum likelihood method and Kolmogorov-Smirnov statistic for parameter estimation. They also propose a novel simulation framework for the estimation of the sampling uncertainty of the power-law distribution. They apply the methodology to streamflow data from 62 USGS stream gauges in Iowa. The key finding of the study is that low-probability quantile estimates using Turcotte’s method result in conservative estimates when compared with LP3 distribution confirming the earlier outcomes.

Sanitary quality of reused water for irrigation in agriculture in Brazil

Reused water is produced from treated effluents, and can be an alternative source of water for agriculture. However, its quality must be assessed to avoid causing damage to human and environmental health. This study evaluated the sanitary quality (bacteriological and physicochemical) of reused water samples for agricultural irrigation, compared with those described in Brazilian and international regulations. Bacteriological analyses were performed, and the results were compared with the norm of the Brazilian Association of Technical Norms (ABNT) NBR nº 13.969/1997. Physical and chemical analyses of the reused water samples were carried out, and the results were compared with the standards described by regulations: Resolution of the State Council for the Environment of Ceará No. 2 of 2017; Resolution of the Bahia State Water Resources Council No. 75 of 2010; and “Guidelines for Water Reuse” from the U.S. Environmental Protection Agency - EPA. According to Brazilian regulations, bacteriological analyses showed that the "chlorinated" and "polished" samples were suitable for agriculture. However, the “biological" sample was unsuitable for use, and showed a high level of thermotolerant coliforms (25.800 CFU / mL). According to bacteriological and physical-chemical analyses, the “polished” sample was only proper for agriculture irrigation. Therefore, the work suggests the creation of federal law regarding agricultural reuse to control the sanitary quality of water for human and environmental health.
 Keywords: agricultural reuse, agriculture, bacteriological and physicochemical evaluation, norms for reuse in agriculture.

Climate risk-informed decision analysis (CRIDA): ‘top-down’ vs ‘bottom-up’ decision making for planning water resources infrastructure

AbstractClimate risk-informed decision analysis (CRIDA) is a guidebook that lays out an evaluation framework and decision procedures to deal with climate uncertainties that are consistent with traditional agency water resources planning frameworks. CRIDA guidelines complement existing institutional guidance on recognizing circumstances when more complex risk-based climate analysis may be needed, above those required by standard planning procedures. The procedures are based on the concept of ‘decision-scaling’ judgments to qualitatively assess levels of future risk and analytical uncertainty stemming from climate change-related uncertainties, and as a guide for choosing specific analytical approaches and appropriate levels of analysis. CRIDA addresses how much detail is appropriate for a given problem setting, depending on infrastructure type and function, whether it is new design or rehabilitation of existing infrastructure, modular design or long-life infrastructure. CRIDA was structured to resolve the contentious issue of deciding under what circumstances a ‘top-down’ climate scenario-driven analysis ought to be conducted versus a more traditional ‘bottom-up’ vulnerability assessment, based on conventional agency project feasibility procedures. The procedures for such vulnerability assessments and planning procedures are well-represented in classical approaches, such as those included in the 1983 U.S. Water Resources Council's ‘Principles and Guidelines’. These commonly used procedures promote normative evaluation protocols and decision rules that generate alternative solutions which minimize risk-cost outcomes.

Representation of agriculture in water governance in São Paulo

Abstract The water resources management model in the state of São Paulo is characterized by the participation of water users from different sectors of the economy within the ambit of River Basin Committees and other organizations of the water management system. The purpose of this article is to present a survey and systematization of the performance of representatives of São Paulo’s agricultural sector in this decentralized and participatory system of water governance. To this end, this article recreates the profile of this sectoral representation in the State Water Resources Council and in the Committees for rural areas with strong agricultural dynamics in the state. The findings of this study reveal significant political and propositional differences between São Paulo’s agriculture and agroindustry sectors. Such differences have to do with the structure and capillarity of the entities that represent these sectors, as well as their divergent concept of management.

Sustentabilidade ambiental e integração na política de recursos hídricos no Brasil: questões inseparáveis

O artigo trata de fatores considerados orientadores da política, da integraçãoe da articulação da gestão de recursos hídricos do Brasil, aspectos queconstam da base legal da política nacional (Lei nº 9.433/1997; capítulo III).Ele enfatiza a avaliação da discussão da política de água e sua interfacecom outras políticas setoriais. Para entender o alcance dos conceitos deintegração e articulação, e dialogar com a prática, serão apresentadasas perspectivas da gestão integrada adotada pela Parceria Mundial daÁgua (Global Water Partnership), intitulada “Gerenciamento Integrado deRecursos Hídricos” (Integrated Water Resources Management), e tambémaquela fundamentada pela Fundação Nova Cultura da Água, quando tratada perspectiva ecossistêmica. Avalia-se como as questões da integraçãoentre políticas e perspectivas estão ocorrendo no âmbito do ConselhoNacional de Recursos Hídricos brasileiro, fórum central das discussõesda política de águas do país. A sistematização dos dados se apoia nolevantamento e na análise das atas e pautas tratadas durante os 20 anos de existência do conselho. As atas foram analisadas com o Programa estatístico R para avaliar a frequência determos citados durante as reuniões. Os temas das pautas foram organizados em seis grandes tópicos: regras de funcionamento, instrumentos de gestão, gestão integrada da água, articulações setoriais, educação ambiental e apresentações. Tornou-se claro que as o maior número de pautas versam sobre as regras de funcionamento que agregam questões administrativas e normas gerais.

Classification of the Juturnaíba Dam: Potential Risk and Damage

A Dam Safety Program aims to reduce the risks to human life, property, and the environment from dam related hazards. In Brazil, despite of the contemporary law about dam safety, there is still no cadastral information nor the classification of risk and associated potential damage to all dams. Besides that, the recent disaster caused by the failure of the Fundao dam, located in Mariana city, Minas Gerais State, is an issue that aggravates the urgency of preventive measures and plans for disaster action. The present study proposes to classify the Juturnaiba dam, which maintains the largest reservoir for water supply in the state of Rio de Janeiro, Southeast region of Brazil. It was sought to analyze the risks and potential damage associated with the dam, in accordance with two classifications: one from the Brazilian Dams Committee and the other from the National Water Resources Council. It was possible to conclude that the Juturnaiba dam potentially presents high risk and associated high rates of damage, both regarding losses of human lives and regarding environmental and socioeconomic impacts. This is mainly due to the poor state of conservation that it currently presents. It is recommended that future studies should assess the slope stability of the earth dam, and that repair work should be implemented on the degraded concrete structures, with recuperation or installation of instruments that would enable monitoring of possible movement of the earth dam.

Salvinia molesta D.S. Mitch.

<i>Salvinia molesta</i> D.S. Mitch.

Estimating Generalised Flood Sew Coeficients for Peninsular Malaysia

Flood estimations based on itting the frequency of occurrence of annual peak discharges using the Log-Pearson Type 3 distribution are commonly used but they are sensitive to the skew coeficients of the gauging stations. The estimation accuracy can be improved by using a weighted average population skew coeficient calculated from the sample station skew and the generalised unbiased skew. The U.S. Water Resources Council (WRC) has documented guidelines for estimating the generalised skew coeficients and published a map of generalised skew values for the United States. The map shows isolines of skew coeficient values and the average skew coeficient for each 1-degree quadrangle of latitude and longitude for the United States. Following the WRC guidelines, many of the state authorities in the US have developed the generalised skew coeficients separately on a state/regional basis. In Malaysia, the Log Pearson Type 3 distribution has been widely used for lood peakestimation but there are no guidelines available for estimating the generalised skew coeficients for use in con–unction with the distribution and as more accurate results can be obtained if these data are available, it is clear that a regional lood skew study is needed. With the regional sew data available, the peak low can be simply and easily calculated with the aid of a software such as HEC-SSP. The aim of this paper is to use the WRC guidelines to derive the generalised skew coeficients using the peakannual discharge data of Peninsular Malaysia for general use.The WRC recommended several techniques for estimating and evaluating generalised s—ew of the Log-Pearson Type 3 distribution for the annual peakdischarges. Station skews (skew coeficients computed from gauging station records) and unbiased and weighted skews derived from these station skews are to be used to develop these techniques. In this study, peak discharge records at 66 gauging stations having 16 or more annual peak discharges in Peninsular Malaysia were selected for computing station skews. Station skew values ranged from -0.831(log10 unit) to 1.475 (log10 unit).The three techniques recommended by WRC used for estimating the generalised skew of annual peak discharges were adopted for this study. These methods are: (1) An isoline map, (2) a prediction equation (3) a regional mean skew. Attempts to develop a prediction equation were unsuccessful. An error analysis showed that the regional mean skew method has a lower MSE (mean square error) than that obtained from the state wide generalised skew coeficient contour map. As a result, the mean station skew for the selected gauging stations can be used to estimate the generalised skew for any gauging site in the peninsula.The mean skew is -0.022 (log10 unit) and the associated mean square error is 0.05 (log10 unit).

Training watershed committee members to aid on the decision-making process for the execution program of the framework of water bodies

According to the National Water Resources Council 91/2008, the approval of the action plan of the framework of water bodies should be carried out through a decision-making process along the participation of the Watershed Committee (CBH). However, decision-making processes involving multiple stakeholders are vulnerable to flaws that can lead to mistrust among members and lack of commitment with the decisions taken. Some of these failures refer to the absence of information, transparency and lack of knowledge of the object of decision. In this context, the use of technological tools as a means to expand social participation has increased considerably. Among these, it is possible to mention the Information and Communication Technologies (ICTs). This paper presents a study about the use of Information and Communication Technologies (ICTs) to aid watershed committee members on deciding about the set of actions for the execution of the framing of water bodies, having the Salitre River Watershed as a study case. To support the decision on selecting the best action plan the Analytic Hierarchy Process (AHP) multi-criteria analysis method was used, for which a Distance Learning course (DL) within the free platform of “facebook” was developed. The analysis of the results showed that through the expansion of online communication and the creation of open forums through websites and social networks, the discussions among the watershed committee members may extend beyond the plenary meetings that occur not very often throughout the year. The application of ICTs presented some advantages regarding to the decision-making process within the CBH, such as: more time to discuss and obtain consensus; increasing access and exchange of information and experiences; transferring of technical information more clearly; and solving problems like inability to travel by the CBH members.

Where Fanny Balbuk Walked: Re-imagining Perth’s Wetlands

Where Fanny Balbuk Walked: Re-imagining Perth’s Wetlands

The Effect of Involving Exceptional Outlier Data on Design Flood Magnitude

The term "outlier" is generally used to refer to single data points that appear to depart significantly from the trend of the other data. Outliers are classified into three types: incorrect observations, rare events resulting from essentially the same phenomena as the other maxima, and rare events resulting from a different phenomenon. Flood frequency analysis was first performed on complete data series (including the outlier) and then on the series with the outlier removed. Results revealed that omission of the outlier data didn’t affect the probability distribution function (Log-Pearson type III), but the design discharge reduced by 60 percent in 10000 year return period from 3320 (m3/s) to 1340 (m3/s). Furthermore, the method proposed by the U.S. Water Resources Council (WRC), and the HEC-SSP software were applied in order to compose outlier data with other systematic data and to modify the parameters of the statistical distribution. Using WRC method, the estimated 10000-year flood was equaled to 1907 (m3/s) by designating the outlier as the 200-year return period and revising the parameters of Log-Pearson type III distribution; that is about 43 percent decrease over the scenario involving the outlier.

Integrated Ecosystem Management of River Basins and the Coastal Zone in Brazil

International society has begun to consider river basins and the coastal zone as one management unit that requires an ecosystem approach. Various countries have undertaken initiatives since the 1970s and have improved the approach to integrated coastal zone management. Brazil has not been one of them. Its sector-based approach to most environmental issues started in the 1980s with the National Environmental Policy Act (Law 6,938/1981). The National Coastal Zone Management Plan (NCZMP) was then approved by Law 7,661 in 1988. Shortly thereafter, the 1988 Brazilian Constitution was enacted, which established the environment as a common good to be used by the entire society but in such a way as to prevent environmental degradation and conserve its quality for present and future generations. The National Water Resources Policy (NWRP) was not enacted until 1997 (Law 9,433/1997). This law established that water resource management in Brazil must take into account estuarine ecosystems and the coastal zone, using an integrated approach. Only in 2006 did the National Water Resources Council (NWRC) create a technical chamber dedicated to developing regulatory measures for integrated management in Brazil. There has been substantial discussion and various proposals to implement it, as outlined in this article. This paper concludes with suggestions for implementing integrated river basin and coastal zone management in Brazil.

Influence of Indian Ocean high pressure on streamflow variability over southwestern Australia

&lt;p&gt; &lt;/p&gt;&lt;p&gt;The seasonal and interannual variability of the southwestern Australia streamflow was examined based on re-analysis dataset from the National Centers for Environmental Prediction / National Center for Atmospheric Research, plus monthly streamflow data from 17 meteorological stations obtained from the Department of Water of the Australian Water Resource Council (1976-2008). Significant findings reveal that since the middle of the last century, the early winter (May-August) streamflow variability over southwestern Australia has been associated with variability in the intensity of the Indian Ocean high pressure (IOHP) system, as well as the zonal movement of the high pressure system across the Indian Ocean. Of note, however, the emphasis in the previous studies has linked the ongoing winter drought in western Australia to changes in sea level pressure, both on a local basis and over larger areas. We introduce objective indices for the area-weighted pressure of the IOHP, and the IOHP area-weighted latitude (IOHLT) and longitude (IOHLN) positions. When the IOHP is shifted to the east, there is less streamflow in the southwestern Australian rivers that are examined in this study. The situation is reversed when the IOHP is shifted to the west, when there is more streamflow in the southwestern Australian rivers. The characteristics of the streamflow pattern are determined for the river catchment areas located around the coastal region over southwestern Australia using principal component analysis. The first principal component taken into consideration describes 84.43% of the total variance. The multiple correlation between the loading of the first principal component scores of the streamflow and the IOHP and IOHLN is 0.54, while the correlation between the southern oscillation index is 0.44. Centers of action indices explain 29% of the streamflow variability, while the southern oscillation index explains only of the 19% streamflow variability. This discovery is of real importance for the definition of the physical mechanism of seasonal (May-August) streamflow variability of southwestern Australian and the IOHP.&lt;/p&gt;&lt;p&gt;&lt;span style="text-decoration: underline;"&gt;&lt;br /&gt;&lt;/span&gt;&lt;/p&gt;

Participatory and decentralized water resources management: challenges and perspectives for the North Paraíba River Basin committee – Brazil

The Brazilian Water Resources Policy (Law 9433/1997) establishes participatory and decentralized management, involving civil society, water users and governmental bodies, with the basin committees as the basis of this process. Fifteen years after its implementation, it is possible to perceive accomplishments, but, at the same time, there are some difficulties in regards to the operation of the basin committees in the country. Considering the North Paraíba River Basin - which is completely included in the State of Paraíba, Northeastern Brazil, and presents great social and economic importance for the state - this article analyzes the process of formation, installation and functioning of its Basin Committee (CBH-PB), focusing on its composition, the reasons for the mobilization and demobilization of its members, the intra-relations between segments, and the inter-relations between the CBH-PB and other entities of the State Water Management System (the Water Executive Agency and the State Water Resources Council). The level of decentralization and the quality of participatory management (as it is being performed at the CBH-PB) are discussed and guidelines are suggested in order to allow greater effectiveness to the committee.

Objective or Multi-Objective? Two Historically Competing Visions for Benefit-Cost Analysis

As they embraced benefit-cost analysis during the mid twentieth century, economists faced several challenges. One challenge was to reconcile two visions for the place of the economist in policy analysis, one limited to providing positive analysis for decision-makers, the other allowing normative judgments. This tension came to a crisis when, in the 1960s, the Water Resources Council introduced multi-objective benefit-cost analysis. The surrounding debate highlights the way philosophical differences can drive the technical details of policy analysis, the way political debates can overshadow academic ones, and the way even social scientists in a narrow subfield can profoundly misunderstand one another.

It’s Time for Standards of Practice in Water Resources Planning

Fifteen years ago, we formalized a disciplined planning approach that we termed Shared Vision Planning. Although we found it immediately beneficial in our planning studies, we wondered whether what we had invented would be short-lived. Perhaps we had invented the water management equivalent of the IBM Selectric? For those readers under the age of 50, the Selectric was an amazingly advanced electric typewriter that was invented about 20 years before the first Apple computer. It turns out that we need not have worried; the consequences of not planning adequately are now headline news, so the idea of disciplined planning— considering the consequences of a decision before it is made—has a renewed luster. We worry, though, that today’s planners are unaware of the planning accomplishments of the past. The fact that much has changed since the 1970s does not mean that previous knowledge is worthless, only that the old lessons must be updated if they are to serve as modern templates for water resource planning. The Water Resources Council established rules for federal planning 30 years ago. In 1973 the Council produced Water and Related Land Resources: Establishment of Principles and Standards for Planning PS and for every study labeled shared vision planning, two or three others use an essentially similar approach but not the label . Now is an excellent time to assemble the

History and Development of the NRCS Lag Time Equation1

Abstract: Many of the hydrologic methods that are used in engineering practice today resulted from the Spring Flood of 1936, which blanketed the Northeastern portion of the United States. Because of the flood damage that was caused by this rainfall‐snowmelt event, many federal agencies including the U.S. Army Corp of Engineers and the Soil Conservation Service (SCS) implemented the hydrologic theories that were available in the literature at this time and developed hydrologic procedures for design flow estimation. Sherman had recently published his unit hydrograph theory in 1932, and later in 1938 Snyder, who had been charged by the Water Resource Council to develop a synthetic unit hydrograph, published his famous paper. The SCS unit hydrograph theory was developed by Victor Mockus in the late 1950s. Most if not all of the theories at that time reported the rainfall‐runoff process for floods as a surface phenomenon, and as such those theories all required some type of a timing parameter to estimate watershed response time. This article documents the development of the SCS lag equation.

Transplanting the TVA? International Contributions to Postwar River Development in Tanzania

This paper focuses on the controversy around the proposed damming of the Rufiji River at Stiegler's Gorge that followed the publication of the 1967 United States Bureau of Reclamation's survey of the Rufiji basin. Recommending the establishment of a National Water Resource Council and the construction of Stiegler's Gorge Dam, the report set off a debate about the river's development. The proposed dam served as a model of river basin development that had been carried by international agencies like the United Nations Food and Agriculture Organization and Bureau of Reclamation to all parts of the world. Based on archival and field work, this paper examines the process by which this American model of river basin planning and technologies came to dominate Tanzania's postwar development agenda. The case illustrates how both international and Tanzanian actors shaped the debate about the transfer of large-scale hydropower projects to postcolonial Africa.

Comparison of two approaches for generation of daily rainfall data

There has been extensive research on the problem of stochastically generating daily rainfall sequences for use in water management applications. Srikanthan and McMahon [Australia Water Resources Council, Canberra, 1985] proposed a transition probability matrix (TPM) model that performs better for Australian rainfall than many alternative models, particularly where long records (say 100 years) are available. Boughton [Report 99/9, CRC for Catchment Hydrology, Monash University, Melbourne, 21pp, 1999] incorporated an empirical adjustment into the TPM model that allows the model to reproduce the observed variability in the annual rainfall. More recently, Harrold et al. [Water Resour Res 39(10, 12):1300, 1343, 2003a,b] proposed nonparametric models for the generation of daily rainfall occurrences and rainfall amounts on wet days. By conditioning on short, medium and long-term characteristics, this approach is also able to preserve the variability in annual rainfall. In this study, the above two approaches were used to generate daily rainfall data for Sydney and Melbourne, and the results evaluated. Both approaches preserved most of the daily, monthly and annual characteristics that were compared, with the nonparametric approach providing marginally better performance at the cost of greater model complexity. The nonparametric approach was also able to preserve the variability and persistence in the annual number of wet days.

U.S. states predict water shortages

Thirty‐six U.S. states anticipate suffering water shortages under normal water conditions within the next 10 years, state water managers indicated in a survey released by the U.S. General Accounting Office (GAO) on 9 July.The report to Congress, entitled, “Freshwater Supply: States' Views of How Federal Agencies Could Help them Meet the Challenges of Expected Shortages,” is the first comprehensive national assessment of water availability and use since a 1978 report by the U.S. Water Resources Council.