It Was the Best of Hydraulic Sections; It Was the Worst of Hydraulic Sections: A Tale of Two Channels

Forum papers are thought-provoking opinion pieces or essays founded in fact, sometimes containing speculation, on a civil engineering topic of general interest and relevance to the readership of the journal. The views expressed in this Forum article do not necessarily reflect the views of ASCE or the Editorial Board of the journal

Moving statistic method (MSM) for quantification of changes in precipitation intensity and dry periods caused by climate change and demonstration on major U.S. cities

Climate change is predicted to (1) increase the magnitude of precipitation over time, and (2) lengthen the time between significant precipitation events and to thereby increase both flooding and drought for some zones of the planet. It is important, therefore, to quantify the degree that populated cities are affected by climate change as measured by both these hypotheses. A rating system is proposed here that uses the multicriteria of both the magnitude and variability of total annual precipitation values to give a rating system to do this. The precipitation moving average and standard deviation are used here and are demonstrated on the 46 most populous U.S. cities. Results show that not all cities have experienced climate change effects, and that Houston has been affected the most, but that New York has more people affected by climate change of precipitation due to its larger population

Clay permeability changes - Flexible wall permeameter & environmental scanning electron microscope

Clays and their composites have been widely used in the past for secondary containment walls for underground storage tanks and landfills. These materials, also called liners, are an inexpensive method of preventing seepage of chemicals into the groundwater from underground storage tanks and landfills. In this study the behavior of clay liners is examined on a microscopic level. The clay fabric changes observed in the images from an Environmental Scanning Electron Microscope will be compared to the permeability changes in clay under similar conditions. The permeability changes will be recorded using a Flexible Wall Permeameter. The presented observations will have important ramifications for clay modification to reduce seepage of chemicals through the clay liner. The experiments are being planned currently and results will be presented at the conference. Copyright ASCE 2005

A direct solution to normal depth in open channels

Normal depth is an important parameter in open channel analysis and has ramifications for flood prediction. Calculation of normal depth can be done by various methods but there is no simple analytical solution. All of the existing methods either have a complex chain of equations or are iterative. A regression equation is presented here that is computationally more efficient than the existing methods and introduces little additional error. Copyright ASCE 2005

Energy savings using biofuel in a developing-country water distribution system

© IWA Publishing 2018. The practical energy minimization algorithm (EMA) is introduced here to determine if a water distribution system (WDS) can be less energy dependent. The EMA is a simple algorithm that can be used by practitioners in the planning and management of WDS. The EMA employs the Jatropha Curcas (JC) tree as a source of oil for fueling water pumps. The EMA is demonstrated on a WDS in Senegal, West Africa, and calculates the level of JC production required to be self-sufficient in fueling the water system to meet drinking, sanitation, and JC irrigation requirements. It was found that the EMA successfully showed that the demonstration WDS can be energy self-sufficient to provide recommended amounts of drinking water for the people and enough irrigation for the JC trees, but only if greywater was used to supplement the irrigation and if a mechanical press was used in lieu of a hand press to extract the oil from the JC leaves. An adequate amount of oil was thus produced to power the required mechanical press as well. Payback periods of significantly less than the life of the required equipment indicate the viability of JC oil as fuel and the feasibility of having an energy independent WDS