Muskingum Method Of Flood Routing Research Articles

The potential trade‐off between artisanal fisheries production and hydroelectricity generation on the Kafue River, Zambia

Summary1. Freshwater resource managers are increasingly obligated to consider the impacts of large river engineering projects on ecosystem services. We evaluated the effect of altered water regime from the operation of a large dam on the production of the downstream tropical floodplain fishery of the Kafue River, Zambia. We compared the benefits of increased hydropower relative to potentially lost fishery production.2. We compiled a long‐term data set consisting of experimental gillnet catches, artisanal harvesting effort and monthly river flows for 25 years prior to and 29 years after the 1977 completion of the upstream Itezhi‐Tezhi Dam. As a metric of the flood regime, we calculated a canonical correlation score for each hydrological year before and after dam closure. For the period following dam construction, we used the Muskingum method of flood routing to estimate ‘no‐dam’ flows through the fishery area and downstream hydroelectric turbines at the Kafue Gorge Dam.3. We compared 16 alternative models of catch per unit effort (CPUE) with and without an effect of water regime on fish population growth rate. Using the two best fitting models, we estimated the total observed fishery harvest and simulated ‘no‐dam’ fisheries harvest and found no significant effect of altered water regime on fishery production.4. We estimate that the large upstream dam increases downstream hydropower production by about $18 million USD per annum. The reduction in fishery production caused by the altered water regime is not significantly different than zero, although the average reduction amounts to about $2.3 million annually. The total estimated value of harvest ranges from $1.3 million to $56 million annually.5. Large observed declines in fish abundance over the 54‐year study period are attributed primarily with similarly large increases in total fishing effort in this mostly open‐access artisanal fishery.6. These results contrast with other examples of the effects of flow alteration on fish, probably because levels of fisheries exploitation on the Kafue River are very high relative to better studied regions on other continents; our focus on the whole fish community; and the unprecedented length of the time series we considered. If the goal is to sustain fishery production, investments in altering flow regime are likely to be less effective than investments to decrease fishing effort.

Approximate Methods for the Estimation of Muskingum Flood Routing Parameters

There are a variety of techniques for estimating the parameters x and K of the Muskingum method of flood routing. One common difficulty in all the approaches is that different storm sequences along the same river reach would typically yield different parameter estimates. The a statistical analysis of these parameters also shows that they are highly variable. As a result achieving of a high level accuracy may not be the principle issue in describing x and K. This paper presents two approximate methods for estimating these parameters rather easily. The first method requires the computation of the slopes of the inflow and outflow hydrographs at their point of intersection, and the computation of the maximum storage within the reach. The second method requires the computation of the inflow and outflow hydrographs at two specific points. Three case studies investigated show that the first method gives estimates for the Muskingum parameters comparable to those derived by traditional estimation procedures for hydrographs showing linear characteristics.

Time Lag Solution of the Muskingum Flood Routing Equation

Use of time lag in the Muskingum method of flood routing is explained by considering some specific examples. Time lag method removes undesirable predicted results which are obtained by the conventional method. A method is also proposed for calculating the time lag. The examples which have been considered are of floods which can be described in algebraic terms; the method is however of general application and can be adapted for numerical computation.

Translatory characteristics of the Muskingum method of flood routing — Comments to reply

Translatory characteristics of the Muskingum method of flood routing — Comments to reply

Some notes on Muskingum method of flood routing

The Muskingum method of flood routing is revisited. A survey of literature indicates that the initial condition proposed by Gill is incompatible with the Muskingum hypothesis, that the translatory characteristics later derived by Gill are based on unrealistic assumptions, and that the assumptions made by Kulandaiswamy are also unrealistic. These issues are examined in this paper. Further, five different methods of parameter estimation are compared for three sets of data reported in the literature and are found to be comparable.

Translatory characteristics of the Muskingum method of flood routing — A comment

Translatory characteristics of the Muskingum method of flood routing — A comment

Translatory characteristics of the Muskingum method of flood routing — Reply

Flooding has been one of the major issues that have seriously hampered the developments of the urban systems, as well as threatened the urban water environments. To mitigate the impacts of floods, it is highly important to identify effective evacuation plans with the aid of computer-based methods. However, effectively identifying the dynamic evacuation route based on the evolution of flooding status is difficult and challenging. To this end, this study develops a Cellular Automata-based Dynamic Route Optimization (CADRO) algorithm to identify the dynamic flood evacuation route (FER), where the hydrodynamics, topography and human response time are incorporated. The proposed CADRO is applied in a suburb of Yangzhou City, China, and results demonstrate the people trapped rate, the mean and maximum length of FERs are shortened by nearly 32.70%, 34.04% and 7.90%, respectively compared with the traditional A* algorithm used for evacuation route optimization. One important feature of the proposed CADRO is that it can identify the dynamical variation of terrain connectivity within the flooding process, thereby offering the optimal FERs. In addition, the impacts of the human response time to the FERs are investigated in this study. It is anticipated that the proposed CADRO can be greatly beneficial to the urban flooding risk management.

Critical Examination of the Muskingum Method

The Muskingum method of flood routing is critically reviewed. The kinematic wave approach is used to compare and contrast the conclusions deducible from the conventional hydrological approach. The importance of the time lag concept is emphasised.

On the Muskingum method of flood routing

On the Muskingum method of flood routing

Translatory characteristics of the Muskingum method of flood routing

Translatory characteristics of the routed flood waves using the Muskingum method are examined. It was possible to remove some ambiguities of the earlier work on the Muskingum method. Particularly, for instance, the occurrence of the negative outflows during the time intervals 0 < t < k is explained as due to the use of wrong initial condition. As such, the method itself is free from this defect.

The IUH of the Muskingum channel reach

The Muskingum method of flood routing involves the assumption of a linear transformation of the flood wave. The instantaneous unit hydrograph of the channel reach corresponding to the Muskingum equation is derived and shown to contain a negative impulse at the origin which explains the Muskingum prediction of negative outflow under certain conditions. The application of the convolution integral in the Muskingum flood routing method is briefly outlined.

A note on Muskingum method of flood routing

Certain anomalies in the use of the Muskingum Equation for flood routing through channels are stated. It is pointed out that they are due to the particular method of solution now being used for the solution of the differential equation. An alternate method of solution is indicated and it is shown to be helpful in determining the conditions under which a flood can merely be translated in a channel reach, without any significant change in shape. The need for using a classical solution of the differential equation instead of the numerical solution, as done at present, is stressed.