1291 HYDROLOGY AND WATER AVAILABILITY 767. The Mahadayi river is a west flowing river, which is also known as Mandovi river or Madei river in the State of Goa. It drains a total drainage area of 2032 sq.km. in the Western Ghats before falling into the Arabian Sea. Out of a total catchment area of 2032 sq.km., 375 sq.km. of catchment area lies in the State of Karnataka and 77 sq.km. in the State of Maharashtra. Rest of the Catchment area i.e., 1580 sq.km. lies within the State of Goa. 768. Three party States, namely the States of Goa, Karnataka and Maharashtra have indicated different values of water availability at different points in the Mahadayi river basin and at different dependability, through their respective Statements of Case / Statement of Claims or Affidavits of the Expert Witnesses or through the evidence of the Expert Witnesses during the course of Cross Examinations which are as under. a. Water availability at 75% dependability and 50% dependability, is assessed, by the State of Goa for: 1292 i. Entire Mahadayi basin i.e., for the catchment area of 2032 sq.km. ii. Usable yield from catchment area of 1523 sq.km. (i.e., after deducting 509 sq.km. from total catchment area of 2032 sq.km. to assess the ‘usable yield’, which according to State of Goa is generated from an area of 1523 sq.km. only) iii. Kotni Dam (independent catchment) with catchment area of 93.19 sq.km., Bhandura dam with catchment area of 32.25 sq.km., Bailnadi with catchment area of 32.33 sq.km., Kalasa (including Haltara and Surla diversions) with catchment area of 25.50 sq.km., Irti Diversion with catchment area of 8.78 sq.km., Irti pickup dam with catchment area of 9.91 sq.km., Katla- Palna Diversion with catchment area of 22.50 sq.km., Diggi Diversion with catchment area of 15.60 sq.km., and Viranjole Diversion with catchment area of 9.50 sq.km. b. Water availability at 75% dependability and 50% dependability, is assessed, by the State of Karnataka for: i. Entire Mahadayi basin i.e., for the catchment area of 2032 sq.km. ii. Catchment area of Mahadayi basin in Karnataka territory (i.e., for catchment area of 375 sq.km.) iii. Kalasa dam (including Haltara and Surla diversion) with catchment area of 25.50 sq.km., Bhandura dam with catchment area of 32.25 sq.km., Kotni Dam site 1293 (including Bhandura dam catchment and diversion of Irti, Bailnadi) with catchment area of 125.44 sq.km., Kotni Dam site (independent catchment) with catchment area of 93.19 sq.km., Bailnadi dam (diversion) with catchment area of 32.33 sq.km., Irti dam (diversion) with catchment area of 8.78 sq.km., Irti Pickup Dam (Independent Catchment) with catchment area of 9.91 sq.km., Katla-Palna diversion with catchment area of 22.50 sq.km., Diggi diversion with catchment area of 15.60 sq.km., and Viranjole diversion with catchment area of 9.50 sq.km. c. Water availability at 75% dependability, 50% dependability and also the average water availability is assessed by the State of Maharashtra for: i. Entire Mahadayi basin i.e., for the catchment area of 2032 sq.km. ii. Catchment area of Mahadayi basin in Maharashtra territory i.e., catchment area of 77 sq.km. 769. The Tribunal notices that the State of Karnataka and the State of Maharashtra have estimated the water availability for the entire Mahadayi basin with catchment area of 2032 sq.km. However, the State of Goa has estimated (a) the water availability for the entire Mahadayi basin with total catchment area of 2032 sq.km., and also (b) the water availability from catchment area of 1523 sq.km. The water availability from the 1294 total catchment area has been termed as “runoff over the entire catchment” i.e., yield from the catchment area of 2032 sq.km. The State of Goa has estimated the water availability from catchment area of 1523 sq.km. i.e., after excluding an area of 509 sq.km. from the total catchment area of 2032 sq.km. It has been termed as ‘Usable Yield’ in his report by Shri Chetan Pandit, Expert Witness for the State of Goa. Exclusion of 509 sq.km. from total catchment area of 2032 sq.km. by the State of Goa for assessment of yield of the Mahadayi basin 770. From the Issue No. 10 relating to water availability, it is apparent that the State of Goa has used three different terms namely (a) annual runoff, (b) annual yield, and (c) annual safe yield. The State of Goa has used: (a) the term ‘annual runoff’ in respect of water availability from the entire catchment area of 2032 sq.km. of the Mahadayi basin; (b) the term ‘annual yield’ in respect of water availability from catchment area of 1523 sq.km. i.e., after excluding an area of 509 sq.km. from the total catchment area of 2032 sq.km. of the Mahadayi basin; and (c) the term ‘annual safe yield’ in respect of water availability from 1295 catchment area of 982 sq.km. i.e., after excluding an area of 1050 sq.km. from the total catchment area of 2032 sq.km. of the Mahadayi basin. 771. Tribunal notices that Issue No. 24 framed for determination is specifically related to exclusion of an area of 1050 sq.km. from the total catchment area of 2032 sq.km. of the Mahadayi basin. Issue No. 24 reads as under. “Issue No. 24: Does the State of Goa establish that for the purpose of estimation of water yield at different dependability, an area of 1050 sq. km. (out of total catchment area of 2032 sq. km.) is required to be excluded?” 772. The Tribunal finds that at Para 179D, pages 214 to 216 of the Statement of Case filed by the State of Goa (Volume 131), State of Goa has also raised the issue of non-inclusion of an area of 1050 sq.km. from the total catchment area of 2032 sq.km. of Mahadayi basin in the CWC Report of 2003, for the purpose of determination of 75% and 50% dependable yield. It is, however, noticed by the Tribunal that subsequently at Para 179N, page 222 (Volume 131), the State of Goa has mentioned that a Report of IIT, Bombay has assessed the catchment area to be excluded as 1296 501 sq.km., and not 1050 sq.km as mentioned at Para 179D. The Tribunal also finds that on the other hand, Shri Chetan Pandit, in his Report of August 2016 (Volume 191), has considered 509 sq.km. as the area to be excluded to assess the water availability in the Mahadayi river basin. 773. Shri Chetan Pandit, Expert Witness of the State of Goa has discussed the related matter under Para 15, page 55 of his Report of August 2016 (Volume 191) and has concluded as under. “Thus, in this case of Mandovi River basin while the total yield may be estimated for a catchment area of 2032 SqKm, usable yield has to be estimated only on the area 1523 Km2 being = 2032-509 Km2.” 774. The above statement of Shri Chetan Pandit, presents an entirely different scenario from what is reflected in the specific issue framed for determination i.e., Issue No. 24 which is based on averments made in Para 179E, page 217, Para 179L, page 221 and Para 179M, pages 221-222 of the Statement of Case of the State of Goa (Volume 131). 775. The issue of exclusion of a part of the catchment area for assessment of yield of the basin has not been addressed in 1297 the Affidavits or the Reports of the Expert Witnesses of the States of Karnataka and Maharashtra. 776. On the suggestion of Shri Chetan Pandit, Expert Witness for the State of Goa, to exclude an area of 509 sq.km. from the total catchment area of 2032 sq.km. of Mahadayi basin, several questions were put to him during the cross examination by the learned Counsel of the State of Karnataka. In reply to questions No. 98 put to Shri Pandit on 3.10.2016, Shri Chetan Pandit stated as under. “The words I have used are “Thus, in this case of Mahadayi River Basin while the total yield may be estimated for a catchment area of 2032 Sq. Km., usable yield has to be estimated only on the area 1523 Sq. Kms. being = 2032 – 509 Km2”. The word “Usable” is important.” (Emphasis supplied) 777. At Para 15, pages 54-55 of his Report titled “Yield Study for Mahadayi River Basin” filed on 4.8.2016 (Volume 191), Shri Chetan Pandit has mentioned that, exclusion of a part of the catchment from the yield studies, is a standard practice and in this regard, he has cited the following cases. 1298 . The Hon’ble Krishna Water Disputes Tribunal has allotted the yield of the Krishna basin only up to Prakasam barrage. The Hon’ble Narmada Water Disputes Tribunal has allotted the yield of the Narmada basin only up to the Sardar Sarovar dam site. The Hon’ble Cauvery Water Disputes Tribunal has allotted the yield of the Cauveri basin only up to an anicut known as the Lower Anicut. The Hon’ble Godavari Water Disputes Tribunal has allotted the yield of the Godavari basin only up to the Dowleshwaram anicut. 778. During the course of cross examination by Shri Mohan V. Kataraki, learned Counsel for the State of Karnataka, Shri Pandit admitted that excluded area in case of Krishna basin was only about 0.72% (reply to question No.