Note of volume flow rate for the , and – MP/INQ/17.1

1.1 This note is a consequence of discussion during Cross Examination of Keith Hendry during Day 10 of the inquiry, 27 June 2018.

1.2 Clarification was sought as to how Dr Studds derived his volume flow rate (F) for the Ship (MSC) as the footnote on page 74 of Phil Studds Proof of Evidence (PoE) (MP/3/A) only referenced the flow station for the River Irwell.

1.3 Leading Counsel for MSCCL/PI(N)L explained that his instructions were that the flow volume for the MSC under dry flow conditions used in modelling given in Dr Studds PoE was derived from data given on the National River Flow Archive (NRFA) for the River Irwell, the River Irk and the River Medlock.

1.4 Dr Studds has confirmed that the flow volume under these conditions was derived from data given on the NRFA for the River Irwell, the River Irk and the River Medlock and a dry weather flow for WwTW, and that the absence of reference to the other values was in error. The dry weather flow value for the three rivers was generated using 95% exceedance (Q95) values given on the NRFA, e.g.

 Irwell (at Adelphi weir) 5.06 m3/s http://nrfa.ceh.ac.uk/data/station/meanflow/69002

 Irk (at Scotland weir) 0.408 m3/s http://nrfa.ceh.ac.uk/data/station/meanflow/69003

 Medlock (at London Road) 0.218 m3/s http://nrfa.ceh.ac.uk/data/station/meanflow/69020

1.5 Similarly, Dr Studds has confirmed that data from the three gauging stations above was also used to generate a MSC volume flow rate for flow conditions in excess of 1 in 5 year flow conditions. The NRFA data was assessed using a Log Pearson Type III distribution analysis which gave the following results:

 Irk – 17.2 m3/s

 Irwell – 195 m3/s

 Medlock – 8.3 m3/s

17002333.1