**2.2.3 Analysis system**

54 Current Issues of Water Management

new simulations an intuitive application was developed as depicted in Figure 11. The user has to follow up the successive forms to define all the data involved in a simulation. New

> Information about the simulation

Link to analysis system

Cross sections visualisation

 Selection of simulation time

 Simulation parameters definition

simulations are defined using default data associated with the selected one.

Fig. 10. Main functionalities of the hydrodynamic models web interface: profile view

Fig. 11. Main form for definition of new simulations data (left) and interface to define data

The script used by this interface is responsible for setting the starting date and duration of the simulations. The presented form allows the definition of the values of river flows at the most upstream open boundaries. It is possible to define a constant value for the entire simulation or a variable law over that period. The image of a dam (as well as images for other hydraulic structures) on the form gives access to a specific new form for setting the opening laws of the gates and orifices (Figure 11 right). Completed the previous steps, the user can execute the model with these new parameters, pressing the "Run" button, located at

time series related to hydraulic structures (right)

the bottom of the main window (Figure 9).

Table results

Graphical results

Animation

River profile detail

Selection of river to present

The main purpose of this system is to simplify the analysis of complex water systems through presentation of synthesized model results and make available tools for evaluation of different management alternatives. The complexity of environmental systems is related to the uncertainty of the system behaviour caused by lack of essential information to describe natural phenomena and due to the simplifications adopted by mathematical models. This complexity is often intensified by the fact that, there are several actors with shared responsibility in solving the existing problems but usually these actors do not work together.

In the design of the analysis system it was considered the integration of different scales involved in the water resources management problems in a simple and intuitive manner, allowing moving from basin scale to the scale of hydraulic structures within the same application. The analysis of management measures under various environmental scenarios, results in a set of simulations that can be stored by the manager of the developed platform. These stored simulations can be analysed by different users of the modelling system.

Through a specific interface (Figure 12) it is possible to manage (store, consult and remove) different simulations generated in the modelling system. This information is organized by rivers and the analysis is carried out through reports available online. Two separated applications were considered for system analysis: one dedicated to the exploration and analysis of results from hydrodynamic simulations and the second committed to the analysis and exploration of results of water quality. The design and features included in the two interfaces are identical, differing only in the type of results available. This division is justified by the expected use of two distinct groups of users (one group focused on quantitative analysis and the other more interested in qualitative analysis).

Fig. 12. Main interface of the analysis system

Web-Based Decision Support Framework for

et al, 1998) and/or based on available field data.

turbines operation must be defined.

**3.1 Models implementation** 

**3.2 Hydrodynamics** 

minutes.

Water Resources Management at River Basin Scale 57

Models implementation followed a comprehensive procedure that includes four main phases: (i) monitoring data analysis; (ii) identification of key parameters including internal processes parameters or open boundary conditions variables; (iii) model calibration base on

All available monitored data was included in the system databases witch facilitate the identification of the relevant hydraulic structures to be included in the model as well as the relevant waste water discharges. The segmentation of the model was defined considering the important influence of the upstream reservoirs in the river flows and the intense occupation (industrial, agriculture and urban areas) of the basin in the downstream areas. In the calibration procedure a hybrid approach was followed: several parameters were established according to proposed values in the literature (Thomann and Mueller, 1987, Chapra, 1997), from previously developed works about river Cávado water quality (Vieira

The hydrodynamic behaviour of the rivers at river Cávado basin is influenced primarily by rainfall regimes in the region and the exploitation of its hydropower facilities. A conceptual framework (Figure 15), where are identified the main structures influencing the hydrodynamic regimes (numbered from 1 to 28) was adopted in order to characterize the data to define the simulation scenarios. For each scenario the rainfall hydrographs and the pumps and

To illustrate the application of the developed platform thirteen hydrodynamic scenarios were defined in order to estimate average monthly flows and the average flow considering the data included in the information system for the entire available monitoring period.

Turbines were considered fully operational during simulation periods and the water levels at reservoirs are considered near its average level for the month associated with each simulation. It was also considered that other outflow gates at dams are closed. The

Finally, on the oceanic boundary of the model, no tidal variations were assumed. It was considered that the water level remains at the mean sea level during the simulation period. All simulations were defined to have duration of 7 days and a computational time step of 15

Figure 14 presents a comparison between the estimated (estimation based on monitoring data) and the simulated values at different rivers locations. The presented simulated results

From the observation of Figure 14 it is possible to find a close proximity between the estimated and simulated results, with the exception of locations 5, 6 and 12. In the first two locations the difference of 5.6 m3/s is due to the introduction of the flow contribution of the sub-basin limited by the Caniçada reservoir and the Febras river at this last location. A similar situation occurs in location 12. In general, all the other simulations results present a

exceptions were the Venda Nova and Vilarinho das Furnas (Figure 15).

refer exclusively to the last instant of the simulation.

notable approximation to the monitored values.

monitored data; and (iv) scenarios definition and simulations execution.

The main window displays a list box with the available simulations results. It also provides an area with indication of possible simulations available for storage (if the user has permission to store simulations) and an area with additional information about the selected river and simulation data. After selecting the river to be analysed, a plan view of the river is displayed with graphical features that represents river reaches, nodes and hydraulic structures (Figure 13).

Fig. 13. Plan view for selection of river features in the analysis system

The plan view, also allows visualization of aerial photos, location names and the river name that are used as auxiliary information for easily locate the conceptual elements of the model (nodes, reaches and hydraulic structures). Based on these elements it is possible to automatically generate a report with results of the selected simulation. The report consists of: (i) general information about the simulation and information about the number of model nodes; (ii) reaches or hydraulic structures; (iii) plant and profile location of the selected element; (iv) representation of the profile view at the initial time; (v) intermediate instant and at the final instant of the simulation; (vi) table of results for the active element; (vii) graph of results for all variables associated with the selected element; (viii) and a statistical summary of these variables over the simulation period.

### **3. Water quality simulations at the River Cávado Basin**

General procedure for setting up models is briefly presented. In order to illustrate the potentialities of the developed technological platform hydrodynamics and water quality simulations results are presented. Some particular problems of the presented river basin are discussed.
