19 1 2008 1 ADVANCES IN WATER SCIENCE Vol119,No11 Jan., 2008 1,2, 1, 2, 2, 2 (11, 210093 ; 21, 541004) :, ph, 12 mm ph ph, ph ph, ; 4 ; 4, : ; ; ; ; : P6411134 ; TV12117 : A : 100126791 (2008) 0120072206, [1 4 ],,,, [3 ] [5 10 ] [11,12 ], [13 ],, [11,14,15 ],,,, [11 ] ( 1),,, 1 Fig11 Locations of the study sites : 2007204203 : (1212010340104 ; 1212010634806) ; (200602) : (1977 - ),,,, E2mail : jcwu @nju1edu1cn, bmnxz @1261com
1 : 73 1,, 1 752 mm 21 100 hm 2, 87154 % [16], NNE SE 1981-1984,,, [16] C 2 1d ( ),, ( 2), 55 ( 3), 01027 61984 L/ s, Ca2HCO 3 2 Fig12 Outfall of the epikarst spring 3 Fig13 Profile of the epikarst spring 2 2, ( Greenspan) : ( 2 ) ph ( EC) 15 min 2003 10, Ca 2 + HCO - 3 ph 3 Horton,, [17 ]?,,,,,,, :
74 19,,, ph EC CO 2,,,,,,, ph,, ph, ph, ph, ph CO 2 [12,18 ], CO 2,,,,, ph, ph,,,,, ph, CO 2, ;,,,,, ph 2003 10 2005 4, : ph 4 ; 4,, ; 4,,,,,,,,,, (1) 2003 11 10, 30 d, 11 mm, 515 mm/ h (2) 2003 12 6 8, 9 d, 2003 10 30 12 5 37 d, 615 mm, 615 d, 43 h, 915 mm, 0122 mm/ h,, (3) 2004 9 21 25, 29 d, 13 mm, 96 h,
1 : 75 (4) 2004 11 4, 22 1315 mm, 2 h, 6175 mm/ h,,, 4 12 mm 1, Table 1 1 Rainfall producing the change of the first and second grade / mm / h / (mm h - 1 ) / mm / h / (mm h - 1 ) 2003210229 1 215 115 117 2003201210 30 1110 2 515 2003211225 26 210 315 017 2004201215 2 410 1 410 2003211226 018 210 115 113 2004203217 23 610 1 610 2003212206 9 415 310 115 2004204213 6 215 215 110 2003212208 2 510 315 114 2004206215 10 215 3125 018 2003212210 2 310 210 115 2004206217 2 210 0175 217 2004202207 23 415 3125 114 2004207230 10 315 0175 417 2004202223 16 515 2125 214 2004208212 5 215 1125 210 2004209221 29 615 110 615 2004210214 18 415 315 113 2004209225 4 615 0175 817 2004211204 22 1315 210 618 2004210213 17 215 1125 210 2005203201 3 615 41 012 2005202225 19 510 715 017 2005203219 1 410 17 012 2005204219 19 215 115 117, 3 ( 46), 2003 10 25 10 28 3 ( 4), 3 415 10 615 mm, 2315 mm, 0166 mm/ h1 ph, 1 1, 1, 2, ph, ph,, ph 4 3 Fig14 All three kinds of change in the dry season ( ) 5 11 h ph 116 ( S cm - 1 ) / h - 0101/ h - 01006 / h, 3 ph, ph 4 h, 2 ph3125 ( S cm - 1 ) / h - 0104/ h 010 / h, 2 3 () ph 3,
76 19 5 Fig15 Second and third grade change in the rainy season Fig16 6 Continued third grade change of epikarst in the rainy season 2004 4 13 15 ( 5), 1 6 d, 2 1 24 h 1, 2 215 3 mm ; 110 214 mm/ h,, 2004 7 20 22 4, 6, 2004 7 20,, 4, 015 9 h, 30 19 2115 14 mm ; 6131 318 4153 315 mm/ h, 4 5, ph 4 4 5,,,,,, 4,,,,,,,,,, [16 ] : [1 ],,,. [M]. :, 19961 [2 ] Walid A, Michel B, Roger G, et al1 Analysis of the karst aquifer structure of the Lamalou area ( H rault, France) with ground penetrating radar[j ]1 Journal of Applied Geophysics, 2002, 51 :97-1061 [ 3 ] Klimchouk A1 Towards defining, delimiting and classifying epikarst : Its origin, processes and variants of geomorphic evolution[j ]1 Speleogene2
1 : 77 sis and Evolution of Karst Aquifers, 2004, 2 (1) :1-131 [ 4 ] Marco T, Diego G, Danilo R, et al1 Investigating epikarst using low2frequency GPR : example from the Gran Sasso range (Central Italy) [J ]1 Bull Eng Geol Env, 2005, DOI 10. 1007/ s 100642005200172y. [5 ] Clemens T, Huckinghaus D, Lield R, et al1 Simulation of the development of karst aquifers : Role of the epikarst[j ]1 Int J Earth Sci, 1999, 88 :157-1621 [ 6 ] Lee ES, Krothe NC1 A four2component mixing model for water in a karst terrain in South2central Indiana, USA1 Using solute concentration and stable isotopic as tracers[j ]1 Chemical Geology, 2001, 179 :129-1431 [7 ] Perrin J, Jeannin PY, Zwahlen F1 Epikarst storage in a karst aquifer : a conceptural model based on isotopic data, Milandre test site, Switzer2 land[j ]1 Journal of Hydrology, 2003, 279 :106-1241 [ 8 ] Aquilina L, Ladouche B, Dgrfliger N1 Recharge processes in karstic systems investigated through the correlation of chemical and isotopic com2 position of rain and spring2waters[j ]1 Applied Geochemistry, 2005, 20 :2 189-2 2061 [9] Aquilina L, Ladouche B, Dgrfliger N1 Water storage and transfer in the epikarst of karstic systems during high flow periods[j ]1 Journal of Hy2 drology, 2006, 327 :472-4851 [10 ] Branka T1 How can the epikarst zone influence the karst aquifer hydraulic behaviour? [J ]1 Environ Geol, 2007, 51 :761-7651 [11 ] David GC, James JB1 The use of Alkalinity as a conservative tracer in a study of near2surface hydrologic change in tropical karst[j ]1 Journal of Hydrology, 1999, 216 :172-1821 [12 ] Zhang C, Yuan DX, Cao J H1 Analysis of the environmental sensitivities of a typical dynamic epikarst system at the Nongla monitoring site, Guangxi, China[J ]1 Environ Geol, 2005, 47 :615-6191 [13 ]. [J ]., 2003 (1) :22-251 [14 ],,,. [M]. :, 20001 [15 ],,,. [M]. :, 20041 [16 ]. [M]1 :, 198711-201 [17 ]. [M]1 :, 20041 [18 ], Chris Groves,,. 2 2 [J ]., 2003, 30 (4) :13-181 Threshold value of epikarst runoff in forest karst mountain area J IANG Guang2hui 1,2, WU Ji2chun 1, GUO Fang 2, LI Hua2ju 2, SUN Hai2long 2 (11Department of Water Sciences, Nanjing University, Nanjing 210093, China ; 21 Karst Dynamics Laboratory, Institute of Karst Geology, Guilin 541004, China) Abstract : An epikarst spring in the forest karst mountain area in the southwestern China is selected for this study1 The con2 tinuous auto2monitoring of the spring s discharge, ph, electrical conductivity( EC), water temperature ( T) and rainfall has been done for more than one year1 The results indicate that, generally, in rainy season, the spring s ph shows a temporary decrease after rainfall, and the spring s EC increases temporally, while the spring s T displays a transitory increase1 Howev2 er in dry season the behaviors of these parameters are different1 According to the spring s different reflection to rainfall ranging from faintness to intensity, the response can be classified into three grades1 The first grade is characterized by unchange after rain in discharge, ph, EC and T1 The second grade shows slow and little change in a part of these parameters1 The third grade indicates a distinct change in all of the four parameters1 Basing on the spring s response, it is determined that the threshold value of runoff in the epikarst is 12 mm of rainfall1 For epikarst, the threshold value is the mark to distinguish be2 tween the effective and invalid rainfall1 It is also an important parameter for the study on the formation of groundwater re2 sources1 Key words : epikarst area ; rainfall ; threshold value of runoff ; forest ; karst area