)* J. Hot Spring Sci. /2 33ῌ++* ,**2ῌ῍   pH  +,+ -./0,
 ,*  2  3   ,*  3  . Changes in Temperature, pH and Flow of
Yubatake-group and Bandaiko Hot Spring
Sources in Kusatsu Spa, Gunma Prefecture
Masayoshi FUSE+ and Hideyuki NAGASHIMA,

Abstract
We studied changes in temperature, pH and ﬂow of Yubatake and Bandaiko sources,
and the changes in pH and ﬂow of Yukawa River, Kusatsu Spa, Gunma Prefecture during
the past ./ years. The temperature of Yubatake source has decreased from 00.3 to /*.+(,and the pH has increased from +./ to ,.+. On the other hand, the temperature and pH of
Bandaiko source have maintained constantly about 3/( and +.1, respectively. Totalamount of ﬂow of these hot spring sources including others were calculated by using the
ﬂow and the amount of hydrogen ion of Yukawa River, where most of hot spring waters
are ﬂowed in. Flow of the Yubatake sources group including Yubatake, Sainokawara andother sources have changed between +*,*** and +2,*** l/min, and ﬂow of Bandaiko source
has changed between /,-** and 2,+** l/min during +0 years. Total amount of ﬂow of thesesources in Kusatsu Spa can be calculated as +2,*** to ,0,*** l/min during the past +0 years,
and was ,/,1** l/min in ,**/. Other data of the total amount of ﬂow in Kusatsu Spa reported by using the di#erent method show less than -,,-** l/min in ,**/. Therefore, we
presume that total amount of ﬂow of sources in Kusatsu Spa is between ,0,*** and -,,***
l/min in ,**/.
Key words : Kusatsu Spa, Yubatake source, Bandaiko source, Yukawa River, ﬂow ofsource+

-11ῌ+1++ .0,ῌ/2. + Fuse Clinic, .0,ῌ/2, Kusatsu-machi, Gunma Prefecture -11ῌ+1++, Japan.
,+0,ῌ20*+ !"#$%&' +ῌ-. , Faculty of Science, Tokyo Universityof Science, +ῌ- Kagurazaka, Shinjuku-ku, Tokyo +0,ῌ20*+, Japan.

99 



ῒ

ῑ

   pH,  !" pH   ./ #$%&'()*+,-./% 01 "2 00.3 34 /*.+ 5/ pH 2 +./ 34 ,.+ 67/%82+31* 9 "2 3/ :; pH 2 +.1 <'23=% 0>?@%A 2 "8/-,!?B1"CDEF3
4G/% 01 HI +0 #  JKLMNO  P
A 2 +*,*** lῌmin 34 +2,*** lῌmin 8<,8 2
0 /,-** lῌmin 34 2,+** lῌmin 01<2,8 QQRSTU(V/% /%8=- HI +0 #WA 2 +2,*** lῌmin 34 ,0,*** lῌmin X O P 8WA (YZ/-,,[\ B%,**/ A 2!] ,/,1** lῌmin =% ^" _#`abc ,**/ !d"$e2 A 2 -,,-** lῌmin /-, .8f%L!"Q"&" "Ngh(i'd ,**/ 
A 2 ,0,*** lῌmin 34 -,,*** lῌmin  Xj(k1lmnmo :    !+ῌ ῏ ῍ ῐ ῎)J *+pq ,,+10 m +pq ,,+0, m ,-r. +,,** m s/d20*( 1d2^t u,vwx3434/-> +,*** 96
,5y8 2 6zz,"34 +,-/* m JKLM k,

3$4  +,,** m {+| 7 }t~   2 !
 +,+/* m 88  +2 098Vd\:%@ /-,%

;34 +300  < 8=/%> 0; :(@ >8?,
 +31. 34*@/-AB(/%,\&8 0x 2 
JKLM8(#dOCD@  P /,<x8<\ >) +33/  ,**/   x14
 " pH 21 + E  ,**2 01

  0,,** lῌmin

2 P FGd H2 pH ,-><,8x8$3=% A 2 -,,-** lῌmin  ,**- I,-=/-2W^ J (?@%A ,->K . s(=-, 0* ,**/
k4 H2,->=-, L.ῌzM +31.   +32.
2"8

PN-'ODEF :vDEF?8z,x(P¡/-, B%  ¢#'34 :vDEF £¤¥¦§¨ QNR ©ª8S/,x(P¡/-, L. +323 +331 +333 2 +3/2 34 +33/ 3- ' T :vDEF

'ODEF($ k4 pH 67 5TU34 «8¬365/-,­-,
2 ª>



U\

P"®'t,-^2 P¯°(V[-,x8V±k1-, 4+332,-2 x14(?@2 /-AB WAB33$4² #(1!Xk1-,8 ®2uvw%@ 0BB5
L!d³Y´"QZµῌ¶µB"[d·¯°8\k1-<% 0x8 d9:¸] -3 +30. ¹µº#]¶»8¼½k1
100) /2 * ,**2 ( pH !"#$%& '+,-./+0123456789:;<=>( ?6 .- +302 &@ABCDE( F
GBHIJKELMNOPQRSTU4 VWXYZ89:[\=>]^ Z56_`-a$ bcdefghijk@A( lm +33,, +33-a, +33-b B
"#$n$Bop / +33- &^]Bq ,*,*** lῌmin rstuviw]^ xu( lm+331 B"#$yLzw]^{|>N}~( ~y$ 

Fig. +

Map of main hot spring sources in Kusatsu Spa (revised from Kikawada, ,**.).
 + 
  ,**. 

Table +Hot Spring
SourceFlow and some properties of main sources in Kusatsu Spaῌ
 + 
 ῌ
TemperatureFlow(l/min)pH(Year)(+33/)(,**/)(+33/)(,**/)(+33/)(,**/)

Yubatake
Shirahata
Netsunoyu
Jizo
Sainokawara
NikawaBandaiko(Subtotal)
Others//41//4//.4/-4*.34/+40
3/4.

/,41
/,4,
/*41
.343
..43
.24/
3.4/

,4*2
,4*0
,4*1
,4*/
,4*2
,4+*
+41*

,4+
,4+
,4+
,4,
,4+
,4+
+40

.5.-1
+5/*2
1.1
-20
+5.**
023
05,**
+/5-01
+2521,

.5*.*
0/3
,32
,/,
+5*12+105,**
+-5--3
+2530+-.5,-3-,5-**

Total
ῌRevised from Nagashima (,**2)
ῌ ,**2 

101 
  ! +3/1#!'

" #!$% +3/2 +32. & +32+"

+32, & () * !+,-./012&3) ()& +32/ +320 +322 ,**0  456-.7 8!9:.56&; <=# 01#! > ?-@A pH,  B C=D
#EFDGHIJKL) FM N+O  pH P QR
S9MT7 U )G,  
VW? XY + !!Z[" #\ +,-/* m ;. <A]^!_9M`$=&#a +300

%bcde9M&)G! !f!<'F

DG& <' &g() +31.

9M?)h)*+)i VW#! FM ,jkl-)m.nAopq,*+)G/01rs2)*+FD ? +31*

9M ,**/

# /3A pH,  C! , -@t , uv =DMQRS!w)T4xyz{-@|HIJ
& +32*

 +32/

M +332  +33*

 !/012 +32/ +322  +31/

![M +331 -G |#! +33/5 pH !}~-@ ,**/!  , !:.<DD 0,,** lῌmin c+)  +  ,**2+332 ! +31/

9M +33/G }~M

A6! 3-.1 pH 6! +.0- ) = ?9M&&)G7 !5  `qq8 #;G& +32*

9M5

!9 3/ # )  ! .,*** lῌmin ;. VW!)qq;=&9

pH !&7 9M ,**/

# +.1 '# )C` FD. +31/

9M +33/

?C :9 ;q  <D
¡C<&=)& =V¢!!Z£[¤>¤(C¥?&;#!:9¦§MD }~M +332-  


XY ,

!_¨@;©ª«)¬W#; @ ­ 9Ma-® ¯°±²³ ! 1 A´B-)µ) %b: ¶ CDF·¸Aµ³E:'FE ¹DGº A!
 E¹-.¸HI+qJ»KFD /35 pH, C! - -@t - uv

QRS!Hf¼+3./

9M ,**/w)T4xyz{-@+HIJ& FM /012 +32/ +320 +322 (½¦) +3/2
102

A pH ! Watanuki +30+

Photo + Bandaiko source on December,,, ,**1.
 +  ,**1
+,
,,


- /2 . *,**2+

 !" pH#$%&'()

Table , Long term changes in ﬂow, temperature and pH of Bandaiko sourceῌ , 
pHῌ
Year

Flow
l/min

+300
+31*

,50**

+31/

Temperature


pH

2-40

+41

30

+41

3+4,

+403
+40

+32*

/5****+

3.42

+32/

.5+***,

3.4-

+33*

/52**

3.42*

+33/

/5-**

3/4.

+41

,***

25+**

,**/

153**

3.4/

+40

+41
-

+41*-

Note
Watanuki and Takano(+31+)
21., pH +.0(Ossaka, +32.)
Ossaka et al. (+332)*+ Hot Spring ResearchCenter (+322)*, Hot Spring ResearchCenter (+32/)*- Yamamoto et al4 (+331)
0,,** l/min,(Kusatsu-machi)
0,,** l/min,(Kusatsu-machi)

ῌData cited from Gunma-ken and Kusatsu-machi o$cesῌ
 

Fig. , Long term changes in temperature and ﬂow in Bandaiko source.
 , 
  +30/ ' +31* ' +31/ '" pH /01 *+332+  23, 456 "/ +30/
' 00.3 789:;<=>  ,**/ '/ /+.0 ?2@A!, BC ,**+ 'DE ,**1 '
D @"FG/D?HIJK!AL M *N .+, O3 #$%P +30* ' /,-2* lῌmin
789:;<= ,**/ '/Q .,*** lῌmin ?2@A!, =D= R'#$%
103 #$%&'()*+,-./ 01$234$%-56&-78-92:;8- <=>?& @AB>.'(*#C$%-56D7E;5
FG !+331 +333"
RS.MN"

HIE !+332" & J/? +33/ @K/?L.MN6 pH .OP !Q

TUV W?XQYZ[ \T]YZ[^S.34_`a$%-5 HIE!+332" & +30/ @9E +33/ @?9b%&cdefghYZ[6\T]YZ[ XQYZ[.346

ijkghYZ[ lkghYZ[.mn_op$q* +32/ @r9E.ijkghYZ[ lkghYZ[.mn& st 2u ,** m vw.w-xyz{.|}? 52./~6
$%-5 FG !+323 +331" & +3/2 @9E +321 @?9b%XQYZ[6\T]YZ[*^S?
#$%w-#*~ YZ[* ? 8/34$%-56_E9?$ .3
4&(.36$%6E7562
/~6$%-5.  s& O& ! " 6
$ _ ¡%N ¢/&£¤ !j[¥d" 685* ¦.§.
s ! ¨©" 9Eª j[¥d_Gb%ῌ=$ +«.s_ ¬῍­© !®
¯ -" ?°$ ¬῍;%9E±²³h69¡%-5 !´ +" µ.A xyz{{ st{¶.+V.
Photo , Yubatake source on September ++, ,**1.
 ,  ,**1
3++

Table -

Year



Flow
l/min

Temperature


pH

Note

0-4/
00*,

+4.1
+4/*,

Ossaka (+32.)*+ Miura (+32.), *, Watanuki (+30+)

0/410043*-+402*-*- Ossaka et al. (+332)*. Watanuki et al. (+31.), Osakaet al. (+332)*/ Ossaka et al. (+332)
Hot Spring Research Center (+322)
Hot Spring Research Center (+322)*0 Yamamoto et al. (+331)//.1 (Kusatsu-machi).5,32*+
/5-2*
.513-

+31*

.5+*1

004/*.

+42*.

.5-+0
-5.+0
-5,33
.5.-1
-5.**
.5*.*

0.42*/
0*4.
/340/041*0/.42/,4/+40

,*/
,
,
,4+*0
,4+
,4+
,4+

/,.1 (Kusatsu-machi)

ῌData cited from Gunma-ken and Kusatsu-machi O$cesῌ
 

104¼NL BL½L¶*s?

Long term changes in ﬂow, temperature and pH of Yubatake sourcesῌ-  pH  ῌ

+3.,
+3/2
+30*
+30/

+31/
+32*
+32/
+33*
+33/
,***
,**/

L ·¸¹9E.ºL »·¸.

7 /2 8 ,**2#$% &'()*+,)-.!/ pH - 0123 456

Fig. -Long term changes of temperature and ﬂow in Yubatake source.
 - 


Fig. . Recent changes in temperature in Yubatake source*.
* ,**+ to ,**/ (Kusatsu-machi O$ce), ,**0 to ,**1 (Nagashima).
 .  ** ,**+  ,**/   ,**0 
 ,**1  ,**0  3  ,**1  1   !"105 !"#$%& '()* ,**0 #+,-$ ./, 012&345!678
9:;<&=>?

 5@AB6:CDE&=>,FG0HIJ K . L MN / O PQRQ2+ST5UVWPQ +30* XPQ ,**/ X?PY$5./5!6 8 pH
5ZX[\:X]^0_>` / XS?a#+b50H& c2? &> pH O , de0fgh[
iOh%, 8O ., PQ -* jk?lm#$%& _+ !6?n%$o&> p`O[iq,fgP-+, +32/ Xr--,*** lῌmin st0uvwxD#$%&=>,yP& !6?

O z{ |}5[\ ~?65:Y$%&0HIJ

/& '()*" +33, O ?LY&./5!6 lῌmin > pH PQ +z+ 58

!6 H molῌmin :B# 5
/ pH 0.2* ?LY&8!6>5uPQCDAB6:`&:#+ c5O OE<$5
0H&50 ./?_2&8
6O5@AB6:#$%&>%
J? %$%& c2? &> ¡¢- +33+ X?LY&£¤5CD@A

B6O¥ ,*,*** lῌmin >h-+
¡¢ , +33* XPQ¡¢ +2 ,**0 X?
LY&5CD@AB6O
Photo - Kusatsu Neutralization Plant (Shinaki Dam Water Quality Control O$ce, December ,-, ,**1).
 - 
 ,**1 +,  ,- 

5ST5UVWPQ¦m5 J?#$`+ ==0 !6 AB6 Y lῌmin >8§t H molῌl pH PQ¨ :Table . Long term changes in ﬂow, temperature and pH of
Yukawa Riverῌ .  pH  !"#$%ῌ
Year

Flow
l/min

Temperature


pH

+30*
+30/
+31*
+31/
+32*
+32/
+33*
+33/
,***
,**/

.25***-05***-15***.-5***-25***-,5***-/5***-.50**-+52**-.5.**

.,
-3
-2
-/
-/
-0
-0
-.
-.4/
-*

,4*/
+42/
,
,4+
,4,
,4,
,4+/
,4+
,4*/
,

ῌData cited from Kusatsu Nutralization Plantῌ

106

6 /2 7 %,**2&    " pH  !

Fig. / Long term changes in temperature and ﬂow of Yukawa River.
 /  

89:;,<=/0123 #HF$ molῌmin >?., %+ @&' .,ABC"  #Y$D %, @& EFGHAIJ'KL" M>ANOP%QR & /0123 #HF$ molῌmin D" %+ @& 

EFG,/0123 #HF$ molῌmin ST" >UVWMXYCZ   pH E[\]/0123 #HF$ molῌmin =FG" ^Y=_.`ZCa., %- @&'b"   #Y$ lῌmin DH/0123 #HF$ molῌmin c>/0124
5 #H$ molῌl ST %, @& Eda.,' ef"g #Y$ D    #Y$ =hiCFG, %. @&'#HF$ molῌmin(#Y$ lῌmin)#H$ molῌlῌ%+ @& E"
#Y$ lῌmin(#HF$ molῌmin*#H$ molῌl

῍#HF$ (#HF$ +#HF$ 

῎

#Y$

῏

(#Y$  #Y$ ,-." #HF$ : /0123 molῌmin, #Y$ :  ῌ 3 lῌmin, #H$ : /01245 molῌl^jkDl 0 mn' op , %+33*& STop +2 %,**0& gD

+2,*** lῌmin ST ,0,*** lῌmin %oq" ,+,,** lῌmin& rE" ^st"   D^ /,-** lῌmin ST 2,+** lῌmin IuJP vDPZA"  gD +*,*** lῌmin ST +2,*** lῌmin I vwAuJZ' .,ABC" QR A.CZZis'   A.C|}

xyg=z{gD" ~jkSTDL.<.CZDiPZ' ,**/ gDoq ,/,1** lῌmin IrB,'
107 

Fig. 0 

Total amount of ﬂow in Kusatsu hot spring sources.
 0 

!"#$%&'()*+,- %./,01 234 5$67849+*(),:;<+'=*+, >? +3/2 +32. @ +3/1 A
BCD,

3E4 CFG -.,*** lῌmin HIJ4*+,- KL MNO1@PQ4*C'R ST1 UVWXY Z[ +32, @ +32+ ABCD,H4* #$% -0,*** lῌmin &'%./,\6]6 ++,.** lῌmin 849+* ,.,0** lῌmin H+^_`4Y
ab

cdefghiBC+*@ 

op=Y#$%B#$qrBsp=Y

#$B%=jk@ a῍lmVntu Gv&' #$f\%w xy %

G=Bza #$B{%p=,5$6|}~6 ~6ῌ&'6]6s6849+*()*
sH4*  -,,-** lῌmin H+^_ *++, G ,**/ ABCD,, abcde ,**0 4&4

cde@ -,,-** lῌmin _aB@-}6|}~6. 0VBCD,

~,Y)Btu'=Y6]67;P=*+,;W,V #$%;X*H/,vHB@+pp&-W,

H4*+, p'B MNO1 -4YBC+*;- -,,*** lῌmin ' >?-3
E4Y +3/1 AKL -.,*** lῌmin B,H ST#1 @MNO Q
D¡¢4*+,vHB£^ H¤¥4*+, ab0

cde ,**0



B@ST#1 H +31. A&'¦§¨B©<4ª)YMNO1 -W« ,**/ A¬­®¯°BF,H H4* -,,*** lῌmin W, ±² #$a῍lm}³BCD,%
HP=,6´µ¶·¸¹&'H« º 0 ab108(),H ,**/ ABC+*@ ,/,1** lῌmincdehiB»¼"¬¯°BF, -,,-** lῌmin F«½+_BX /2  ,**2

 pH  

   -,,-** lῌmin   !"#$%&'() *+,- ./&0% 1+23)   45 678 9:;< ,/,1** lῌmin   => ?!@?A%'()%

? ,**/
9 -,,*** lῌmin   "B C%DE, G F ,0,*** lῌmin  H# I 4J 3

9% "$+%() 

 IKL &MC   +  (OPQR'S

   &&M'N  )*+,&T0UVRW(<&X - T-UV , G 1.Y /Z[\]0T-%^_1'.Y#  `aRbcC*, d23e fgh4 Pij#5678=k%^lm'%.Y+nG9)  4J 0%o&1%lm'%.Y  p9
T-#qrR1 :s;t+%()  Fu? ῏R<v ]=C 1+4Jw>?, G῎?@x / AByzCR<{<DE>wῌ|}FGwh4~HIJ o C ῌῑῐ῍
JKLM +32, : J;t  -, +*/῍+,-.
IN ,**. : OAP)*9XQRR  ST
(UV pp. .+῍00 W X

YZ[ +33, :  

I \ /,0  03῍1/.

YZ[ +33-a : ]) \ /-1  /.῍0/.
YZ[ +33-b : ])^ \ /.+  +**῍+*..
YZ[ +331 :  /Z[\ῌῌ_`aῌbῌ /cdMVe pp. ,/῍0. uf g¡ S¢h?z ,**/ : i£¤¥¦ +*  1- +, +,῍+..
§¨j©k +3/2 :   @x\ª «¬ No. +§¨j©k +32. :    ­ _1Vῌ D­V®¯°V pp.
-/-῍-0. DE> 

lm±² ,**2 : _`a RC  /cdMVe pp. 1,῍21
uf g¡ S¢³´µn +32. :  [\¶¥ ­ _1Vῌ D­V®¯°V pp. 31῍+1, DE> D .

³´µn ³´o p2· B¸qM B>r su¹º IN tNu +332 :   v  I  .1 +00῍+12.
»«¬ +32/ :  + ©@x\ª¼ +῍., w»«¬ +320 :  , ©@x\ª¼ +῍/* w»«¬ +322 :  - ©@x\ª¼ +῍+*/ w»«¬ ,**0 : p) +1,  .x@x½y\ª¼ +῍+,. w

Watanuki, K. (+30+) : Geochemical studies on acid hot springs. Sci. Pap. Coll. Gen. Educ. Univ.
109 Tokyo, ++, ,*/ῌ,,-.

  +31+ : ! + "  +31. : &'()*+,-./01234#$% 2 3ῌ+/.
56)7*869: ,/ ,0ῌ-+.
 +323 : ;<6=>  -3 ,3ῌ-/.

 +331 : ?@AB 

?@ABῌCDῌEFGῌHIῌJ ?KLMNO pp. -ῌ,+ PQRST UV +333 : 

6WXYZ

6[\ .3 3*ῌ32.

B<]^ _`ab cdef ghij khlm nop^ Pqb _rst +331 : 
?@Buv6110

6wxyz{W .1 02ῌ1/.