Results and Discussion

An executable file is provided for this application and by executing, the login form is displayed as given in Fig. 2. This allows a user to enter the name and organization for existing users and new users are prompted to create a new profile. The main menu contains Login, Hydro module, Help, Exit. Hydro menu module as shown in Fig. 3, has sub menu;

• Mini/Micro/Small Hydel projects

• Data display

The menu option Mini/Micro/Small allows user to enter general information such as location details, Flow data, Period (yearly/monthly/daily), Method for assessment of energy. User is allowed to enter the head height details if flow data is known. The Query option gives the average precipitation. Figure 4 provides average flow calculation. If there is no flow data then the user is allowed to choose any of indirect methods i.e., Empirical or Rational method as given in Fig. 5. If there is no precipitation data then user is allowed to choose data from near by station (IMD observatory station).

Stream gauging is carried out using a current meter every month. Stream discharge ranges from 1.12 (August) to 0.015 (m³ S^-1) (in February) for Boosangeri. In the case of Muregar, it ranges from 1.395 to 0.026 (m³ S^-1). This indicates that streams of this kind are seasonal. Power generated during June to September is sufficient to meet the energy needs of the nearby villages.

Empirical method: Empirical relation between variables nmoff and precipitation is given in DSS (equation 1). If the user selects Empirical method then the query option

gives the average precipitation as shown in Fig. 6. The Next option as shown in Fig. 7 prompts the user to enter area of cross section in sq.m and calculates yield based on the values of Precipitation and runoff.

Rational method: Figure 8 is shown if rational method is chosen. This method is a relation approach to obtain the Yield of catchment by assuming a suitable runoff coefficient, which varies, based on soil type, vegetation, geology etc. Next option displays the catchment area and prompts user whether precipitation details are available or not as shown in Fig. 9. If the precipitation details are available then user is allowed to enter Sub-catchment details as given in Fig. 10. The Query option calculates precipitation and yield based on the sub-catchment area and co-efficient.

In order to estimate the hydropower potential of ungauged streams, either the rational or empirical relationship of runoff and precipitation is used. The study employs rational method for estimating the hydro energy potential.

A suitable runoff coefficient (which depends on catchment type) is assumed to derive monthly yield in rational method. For each site, Yield (Y) is computed with the knowledge of catchment area (A), catchment coefficient @ and precipitation (P) using equation 2. An attempt has been made to compute the monthly yield from catchments by this method and subsequently the power that could be harvested from the streams. This corresponds with the power computed by the direct method (of the gauged streams Boosangeri and Muregar). Hence, rational method is used to compute hydropower of ungauged streams.

Power and energy calculation: Power is calculated based on flow data and head height, as given by equation 3. Energy option calculates hydro energy based on turbine generator efficiency, period and power as given by equation 5. Figure 11 gives energy calculation. By pressing Graph button, user will be able to view Graph form. It displays graphical representation of hydro energy variation with respect to time as shown in Fig. 12.

Figure 13 gives the option to calculate power and hydro energy using empirical method. Graphical representation of hydro energy derived from empirical method is displayed by graph option as shown in Fig. 14. The values obtained from the sub catchment yield are used to calculate power using rational method. This power is used to calculate energy as given in Fig. 15. Graph option displays graphical representation of energy derived from rational method as shown in Fig. 16.

The study explores the possibility of harnessing hydro potential in an ecologically sound way (by having run-of-river plants with no storage options) to suit the requirements of the region. The Sirsi, Siddapur and Yellapur taluks in hilly terrain amidst evergreen forests with a large number of streams are ideally suitable for micro, mini or small hydro power plants. Monthly stream gauging at Muregar and Boosangeri has revealed that mini hydro power plants could be set up at these sites. The stream at Muregar is perennial, with a flow of about 0.26 (m³ S^-1) during summer and power of the order of 10-20 kW could be generated, while during the monsoon power of 300-400 kW could be harnessed.

Computations of discharge by the empirical or rational method, considering precipitation history of the last 90 years and the subsequent power calculated is in conformity with the power calculations done based on stream gauging. Based on this field experience of gauged sites, an attempt has been made to compute water inflow (using the indirect method), hydraulic power available and energy that could be harnessed monthly for all ungauged streams in the Bedthi and Aghnashini river catchments. It is estimated that about 720 and 510 million k Wh of energy can be generated from various streams in Bedthi and Aghnashini catchments.