The meeting which thinks about fishway of Otagiri River Holdings document for description March 6, 2003 Ministry of Land, Infrastructure and Transport Tenryugawa upstream construction office

Ⅰ． Otagiri River ecosystem investigation １． An investigation purpose Investigate inhabiting circumstances of a creature inhabiting Otagiri River and grasp this investigation and evaluate the influence that an SABO facility and SABO construction give them and contribute to a future sand control business. ２． The investigation year ・ 2001 ・ 2002 ３． Investigation item about fish ・ Fish inhabiting distribution investigation (in 2001, I carry out twice of 14) ・ Fish move circumstances investigation (I run for from 2001 to 14 and carry it out) ・ Fish move circumstances investigation (I run for from 2001 to 14 and carry it out)

４． Fish inhabiting distribution investigation ○Investigation section To grasp distribution circumstances in inhabiting ground; investigation section ○An investigation enforcement day From 13 to 14 on November in 2001 From 3 to 6 on November in 2002 ○An investigation method Set each investigation section to 100m, and it is inhabiting class by diving visual inspection

Table 2 H13 fish findings (a unit:) Table 3 H14 fish findings (a unit:) ○Brief description of a result ・ Char, Amago (discharged) A difference is seen in an authentication population in each investigation section by a year. ・ A miller's thumb (not discharged) Ccompare it in 2001, and 2002 tends to increase. With and a char is not confirmed with one - 1,1-2 one - 3,2-1,3-2,4-2,5-1,6-1, a lot of authentication individuals decreases with three - 1,4-1 with 2-2 of the thing which is an about the same authentication population adversely this year. 。

５． Fish move circumstances investigation The main investigation carried out whether the char which I released went up upstream to grasp whether you went down to the down stream. I performed the capture every each bed sill mechanic. In addition, I performed the capture by casting net every each bed sill mechanic, but performed the capture by a small fixed shore net in section from the 6 bed sill mechanic down stream which I discharged it into of upper reaches. In addition, a small fixed shore net established by one network to right and left rock of a style right under each bed sill mechanic in one evening and captured it. ○ Investigation section I intended for sections from a railway bridge of investigation section JR to Komagane dam. ○ An investigation method I identified capture as a small fixed shore net with casting net with the char which I released. A liberation place and an authentication place of a figure 2 char ・ Discharge day ： From 15 to 16 on November in 2001 ・ A liberation place ：・ The 6 Groundsel down stream 800 individuals (a left ventral fin cut) ・ Otagiri SABO downstream of a dam 100 individuals (a right ventral fin cut) ・ Capture day ： From 23 to 26 on July in 2002 ・ A capture place ： A whole investigation section It was authentication of one individual at the place where it released it to that the char which I released in November was confirmed as a result of investigation. This reason that, as a result, is thought about, 1.It was carried away after liberation by an angler.2 ． It was carried away downstream by floods of July. Two ways of の was thought about, but it was hard to think that an angler could carry it away because the section concerned was catch and release section and thought that I was very likely to be downward flow by freshet.

６． Going up circumstances investigation of Groundsel I carried out the main investigation to check whether each bed sill mechanic could go up. ○Investigation section I intended for Groundsel from 9 Groundsel to prefecture installation Groundsel of the Komagane dam down stream. ○An investigation method I confirmed going up distribution circumstances by inspection I went under water, and to see the char which I released again. ・ Discharge day ： October 12, 2002 ・ Authentication day ： No. 1 from 23 to 24 on October in 2002 ・ A liberation place ： 9, 8, 7, 6 No. 2 from 1 to 2 on November in 2002 The 3 Groundsel down stream No. 3 from 13 to 14 on November in 2002 ○Attachment grounds of the investigation time ・ Liberation avoided freshet of typhoon and sentenced you to October. ・ The authentication decided to perform it until the middle of November in consideration for going up action operator of the breeding season of a char. ○Grounds of a liberation place ・ 9 considered going up of fish; because is a bed sill mechanic of the down stream most; (with step-type fishway). ・ Because 8, 7, 6 are bed sill mechanics of a different type each; (all cross section fishway). ・ It was a bed sill mechanic of the same type, and 6, 5, 4 released it to the 6 down stream. ・ So that upstream is step-type fishway from 3, but only 3 is different in a structure of fishway (2, upstream, 9 and about the same type).

７． Fishway circumstances-like of Groundsel 査 I measured it about overflow water depth or water depth of the dam down stream to grasp the present conditions such as fish way about Groundsel (9 Groundsel, Kiriishi Groundsel) considered for going up of fish. ・ An investigation enforcement day ： October 11, 2002 ・ Investigation object Groundsel ： 9 Groundsel – Kiriishi Groundsel (except 1 Groundsel) Depth of overflow section Water depth of overflow section Water depth of rest ground Depth of rest ground Drop of the surface of the water A measurement point of figure 5 dam Water depth of down stream edge Depth of down stream edge Drop of the surface of the water (the whole) （ one step) Accumulation of sand gravel