Learning outcomes of the course unit
The course aims to supply the necessary knowledge useful for the design of the most common hydraulic works that a Civil Engineer meets in the professional experience: aqueducts and urban drainage systems. Each topic is developed both at theoretical approach supplementing, where necessary, hydraulic and hydrology background, and supplying the most suitable, by a technical-economical point of view, design solutions.
Hydraulics is strongly suggested.
Course contents summary
General concepts, water requirements, Needs and their temporal variations. Population forecasts, time prospects of design. General schemes. Division in more networks in case of marked difference in height. Pressure in different working conditions.
Intakes. From springs, from free surface bodies and lakes. Groundwater motion: conductivity, Darcy’s law. Dupuit’s hypothesis. Complete confined wells, uncomplete and phreatic wells. Draining trench.
Pipelines. Flow regimes and flow resistance formulas: Moody’s diagram. Check of gravity pipelines: discharge computation for schemes with two and three reservoirs, even in case of summits and sections with free surface motion; working of a pipeline with given input discharge. Design of gravity pipelines: analysis of the route, design of pipes in two reservoir schemes, economic design for schemes with more than two reservoirs, design in case of marked difference in height or summits; working piezometric lines; break manholes, dissipation valves, venting valves, outlets, try parts, special parts. Economic design of pipelines with pumping system; characteristic curve of pumping system, serial and parallel pumping. Unsteady flow in pipelines with pumping system. Design of surge tanks with inelastic hypothesis.
Pipes. Materials for pipelines and their characteristics; selection criteria of pipes; junction types, laying and testing of conduits. Accessory devices and valves.
Reservoirs. Main operations of reservoirs; design of compensation volume of reservoirs; fire prevention and reserve volume. Management of inadequate storage volumes; modulation of input discharge, stretching thread method. Constructive characteristics of reservoirs.
Distribution networks. Types of network, spatial division of water supply; sketch of supply. Head losses in pipes with uniform discharge supply. Check of supply networks.
Urban drainage systems
General concepts. Aims, network types (unitary or separated); district and local networks. Technical-economical analysis for the selection of the best solution. Population studies and long-term forecasting. Analysis of civil and industrial users. Plano-altimetric outline of the drainage network.
Estimate of waste sewage. Mean daily annual discharge, discharge of the day with maximum use, minimum flow, maximum flow. First flush water, rain discharges to be treated.
Estimate of storm sewage. Design return period. Hydrology revision: probabilistic investigations on intense rainfalls; rainfall intensity-duration curves; design hyetographs, infiltration capacity and surface detection. Hydrologic models of rainfall-runoff transformation; rational method, travel time and storage method; parameter calibration. Outlines of physically based methods; Kinematic wave on plane surface; free surface unsteady flow equations; transitions.
Design of conduits. Hydraulic computations of conduits. Sewer washing. Manholes, private entries, venting devices.
Spillways. Spillway role. Constructive characteristics. Outflow discharges and pollution transferred to recipients. Regulations. Lateral spillways: theory and design. Leaping and front weirs (outlines).
Siphons. Constructive sketch; design and hydraulic verification. Cleaning.
L. Da Deppo, C. Datei, V. Fiorotto e P. Salandin: “Acquedotti”, Cortina Ed., Padova, 2000.
L. DA DEPPO e C. DATEI: “Fognature”, Cortina Ed., Padova, 1997.
G. BECCIU, A. PAOLETTI: Esercitazioni di Costruzioni Idrauliche, CUSL, Milano, 2000.G. IPPOLITO: “Costruzioni Idrauliche”, Liguori Ed., Napoli, 1993.
V. MILANO: “Acquedotti”, Hoepli Ed., Milano, 1996.
AA.VV. “Sistemi di fognatura”, Hoepli Ed., Milano, 1997.
G. NOSEDA: Problemi di moto vario, DIIAR, Politecnico di Milano (1970).
G. NOSEDA: Correnti permanenti con Portata variabile lungo il percorso, DIIAR, Politecnico di Milano (1970).
A. PAOLETTI: Sistemi di Fognatura e di Drenaggio Urbano, CUSL, Milano, 1998.
Numerical exercises about the topics listed in the program.
Written test about the two parts of the course: acqueducts and sewer network. The test consists of three numerical exercise each that can be solved with the help of pocket calculators. Because of the complexity of the computations, each test lasts three hours.