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August Colding was one of the three pioneers who in the mid-1800s almost simultaneously and independently formulated the first law of thermodynamics, the two others being Robert Mayer and James Joule. This first, significant achievement was followed by a sequence of other ground-breaking discoveries within a broad range of disciplines: magnetism, steam power, gas production, hydraulics, soil physics, hydrology, heating and ventilation, meteorology, and oceanography. Moreover, he made a significant contribution to the understanding of the spread of cholera. In hydrology, he used evaporation experiments to obtain water balances. Independently, he formulated Darcy's law and was the first to calculate the water table between drainpipes and the piezometric surface in confined aquifers. His main occupation, however, was chief engineer in Copenhagen, where he modernized the city by introducing groundwater-based water supply and building a waterworks delivering pressured, clean water into houses, a gasworks and gas-based street lighting, and a citywide sewage system. Colding has not been as recognized internationally as he might deserve, probably because most of his publications were written in Danish. Even in Denmark, he seems today almost forgotten. This paper highlights his most important scientific contributions, in particular his achievements in hydrology, hydraulics, meteorology, and oceanography. [ABSTRACT FROM AUTHOR]

This paper presents a groundwater management model, considering the interaction between a confined aquifer and an unlooped Water Distribution Network (WDN), conveying the groundwater into the Water Works distribution mains. The pumps are controlled by regulating the characteristic curves. The objective of the management is to minimize the total cost of pump operations over a multistep time horizon, while fulfilling a set of time-varying management constraints. Optimization in groundwater management and pressurized WDNs have been widely investigated in the literature. Problem formulations are often convex, hence global optimality can be attained by a wealth of algorithms. Among these, the Interior Point methods are extensively employed for practical applications, as they are capable of efficiently solving large-scale problems. Despite this, management models explicitly embedding both systems without simplifications are rare, and they usually involve heuristic techniques. The main limitation with heuristics is that neither optimality nor suboptimality bounds can be guarantee. This paper extends the proof of convexity to mixed management models, enabling the use of Interior Point techniques to compute globally optimal management solutions. If convexity is not achieved, it is shown how suboptimal solutions can be computed, and how to bind their deviation from the optimality. Experimental results obtained by testing the methodology in a well field located nearby Copenhagen (DK), show that management solutions can consistently perform within the 99.9% of the true optimum. Furthermore it is shown how not considering the Water Distribution Network in optimization is likely to result in unfeasible management solutions. [ABSTRACT FROM AUTHOR]

In 1843 Ludvig August Colding stated the first law of thermodynamic on the conservation of energy as one of three scientists, who independently and almost at the same time found this result, the two others being Julius von Mayer and James Joule. Subsequent scientific work covered a broad range of disciplines: Thermodynamics, magnetism, steam power, hydraulics, soil physics, hydrology, heating and ventilation, meteorology, and oceanography. In 1853 he described the likely courses for spreading of the Copenhagen cholera epidemic together with the chemist Julius Thomsen, one year before John Snow in London gave the final proof for the route of the infection. As Chief Engineer in Copenhagen, Colding subsequently became responsible for building the first water works in the city as well as for gas lightening and sewerage. He planned and projected the water supply based on water from a nearby lake but augmented by groundwater originating from upstream artesian wells being led to the lake through a canal. The piped water in the city was pressured by steam power supplemented by an elevated consumption equalisation reservoir water outside the city. Based on measurements of the inflow to the wells, he later came to the same general law for movement of water in the soil as Darcy without knowledge of Darcy's work. In addition, he analysed soil water and drainage as well as evaporation from a free surface. Moreover, he described the free surface patterns in flowing water and determined the necessary slope for self-cleaning pipes. Colding developed synoptic weather maps and examined thoroughly wind systems and ocean currents including the Gulf Stream, a hurricane that hit St. Thomas (Virgin Islands) in 1971 and flooding of the Danish islands Lolland and Falster in 1972. He lectured at the Technical University of Denmark, where he became adjunct professor in 1869, and in 1871, he was simultaneously with Joule awarded an honorary doctoral degree at the University of Edinburgh. [ABSTRACT FROM AUTHOR]