Table S1. Results of statistical analyses at each monitoring station.

Depth Cross-Correlation* Regression* Harmonic Analysis** Watershed Well Station (m) CCF. Time Lag Slope R2 Tidal Effect Aquifer Type Gapyeong 7.5 - ND 0.991 0 0.94 0.98 Gapyeong 130.0 - ND Gangneung 11.0 - ND 0.995 0 0.98 0.99 Hongjae 69.0 - ND Gwangmyeong 13.5 K1,S2 UC 1.000 0 1.00 0.99 Cheolsan 84.0 K1,S2 UC Gimpo 15.9 K1,S2 UC 0.915 0 1.11 0.84 Gimpo 80.0 K1,S2 UC Namyangju 12.0 K1,O1,S2,M2 SC 0.970 0 0.53 0.94 Byeolnae 70.0 K1,O1,S2,M2 SC Donghae 12.0 - ND 0.999 0 1.02 0.99 Gwiun 17.0 - ND Bucheon 22.3 K1 ND 1.000 0 0.99 0.99 Okgil 70.0 K1 ND Samcheok 10.4 - ND 0.930 0 0.86 0.86 Gagok 70.0 K1 ND Seoul 20.0 M2,K1, S2 C 0.998 0 0.98 0.99 Magok 70.0 M2,K1, S2 C Sokcho 12.0 K1,S2 UC 0.995 0 0.95 0.98 Nohak 70.0 K1,S2 UC Siheung 16.4 K1,S2 UC 0.953 0 0.60 0.90 Gunja 62.0 K1,S2 UC Han River Anseong 17.0 K1,S2 UC 0.995 0 0.93 0.99 Basin Samjuk 49.0 K1,S2 UC Yangyang 11.0 - ND 0.988 0 1.05 0.97 Sonyang 68.0 - ND Yangju 10.0 S2 ND 0.999 0 1.07 0.99 Gwangjeok 70.0 K1,S2 UC Yangpyeong 9.5 K1 ND 0.999 0 1.04 0.99 Gaegun 70.0 K1,S2 UC Yangpyeong 11.4 K1,S2 UC 0.967 0 2.09 0.93 Yangdong 69.0 K1,S2 UC Yangpyeong 11.0 K1,S2 UC 0.973 0 0.95 0.94 Yangseo 70.0 K1,S2 UC Yeoju 15.0 - ND 0.999 0 0.98 0.99 Jeomdong 70.0 - ND Yongin 12.0 - ND 0.623 0 1.04 0.38 Namsa 70.0 K1,S2 UC Yongin 9.5 - ND 0.591 0 0.58 0.34 Mapyeong 63.0 - ND Wonju 20.0 K1,S2 UC 0.988 0 0.95 0.97 Myeongryun 70.0 K1,S2 UC Wonju 8.8 K1 ND 0.992 0 1.12 0.98 Munmak 63.0 K1,S2 UC Eumseong 16.0 - ND 1.000 0 1.00 0.99 Saenggeuk 70.0 - ND Table S1. Cont.

Cross-Correlation* Regression* Harmonic Analysis** Watershed Well Station Depth CCF. Time Lag Slope R2 Tidal Effect Aquifer Type Uijeongbu 11.0 - ND 0.960 0 0.99 0.92 Singok 70.0 K1,S2 UC Ichoen 9.6 K1 ND 0.998 0 1.00 0.99 Yulhyeon 63.0 K1 ND Injae 15.8 K1 ND 1.000 0 1.00 0.99 Nammyeon 70.0 K1 ND Injae 10.0 - ND 0.993 0 0.96 0.98 Injae 70.0 - ND Incheon 15.0 M2,K1,S2,O1 C 0.964 0 1.08 0.93 Yeonsu 70.0 M2,K1,S2,O1 C Jeongseon 42.7 - ND 0.939 0 0.24 0.88 Jeongseon 70.0 K1,S2 UC Jecheon 11.4 S2,M2 SC 0.972 0 1.16 0.94 Goam 70.0 S2,M2 SC Cheonan 18.4 - ND 0.999 0 0.99 0.99 Seonggeo 70.0 - ND Chuncheon 10.0 K1,S2 UC 0.986 0 1.00 0.97 Sindong 70.0 K1,S2,M2 SC Chuncheon 12.0 K1 ND 0.986 0 0.94 0.97 Udu 70.0 K1,S2 UC Chungju 14.5 S2 ND 1.000 0 1.02 0.99 Gageum 70.0 S2,M2 SC Chungju 11.9 K1,S2 UC 1.000 0 1.02 0.99 Han River Dongryang 72.5 K1,S2 UC Basin Paju 15.0 K1,S2 UC 0.677 0 0.16 0.45 Maekgeum 40.0 S2,K1,M2 SC Pyeongchang 15.0 K1,S2 UC 0.926 0 1.02 0.85 Bongpyeong 70.0 K1,S2 UC Pyeongchang 15.0 - ND 0.992 0 0.96 0.98 Pyeongchang 70.0 K1,S2,M2 SC Pyeongtaek 15.0 S2 ND 0.988 0 1.16 0.97 Anjung 70.0 K1,S2 UC Pyeongtaek 10.3 K1,S2>M2 SC 1.000 0 1.02 0.99 Tongbok 69.0 K1,S2>M2 SC Pocheon 23.0 K1,S2>M2 SC 1.000 0 1.01 0.99 Yeongbuk 70.0 K1,S2>M2 SC Hongcheon 12.0 K1 ND 0.993 0 0.98 0.98 Hongcheon 70.0 K1 ND Hwaseong 10.0 K1,S2 UC 0.859 0 0.84 0.74 Yanggam 70.0 K1,S2 UC Hwaseong 15.0 K1,S2 UC 1.000 0 0.99 1.00 Ujeong 70.0 K1,S2 UC Hwaseong 10.0 K1,O1,S2,M2 SC 0.954 0 0.78 0.91 Paltan 70.0 K1,O1,S2,M2 SC Hwacheon 21.4 K1,S2 UC 0.955 0 1.15 0.91 Gandong 70.0 K1,S2 UC Hwacheon 12.0 K1 ND 0.537 0 0.63 0.29 Sangseo 70.0 K1,S2 UC Table S1. Cont.

Cross-Correlation* Regression* Harmonic Analysis** Watershed Well Station Depth CCF. Time Lag Slope R2 Tidal Effect Aquifer Type Geojae 10.0 K1,S2 UC 0.457 0 0.78 0.20 Sinhyeon 68.0 - ND Geochang 10.6 - ND 0.997 0 1.02 0.99 Geochang 69.0 - ND Gyeongsan 11.0 K1,S2,M2 SC 0.763 0 0.82 0.58 Namsan 70.0 M2,S2,K1 C Gyeongju 12.0 K1,S2 UC 0.198 0 0.16 0.03 Geoncheon 70.0 K1,S2,M2 SC Gyeongju 6.8 - ND 0.569 1 0.39 0.31 Sannae 65.0 M2,O1,S2,K1 C Gyeongju 25.0 - ND 0.412 0 0.36 0.17 Yangbuk 70.0 K1,S2,M2 SC Gyeongju 8.8 - ND 0.260 -2 0.08 0.05 Cheonbuk 60.0 - ND Goryeong 7.0 K1,S2 UC 0.986 0 1.01 0.97 Goryeong 65.0 K1,S2 UC Gumi 18.5 K1,O1,S2 ND 0.748 0 0.63 0.56 Dogae 100.0 M2,S2,O1,K1 C Gumi 8.5 - ND 0.996 0 0.96 0.99 Wonpyeong 70.0 S2,K1, M2 SC Gunwi 10.0 K1,S2 UC 0.792 0 0.55 0.62 Uiheung 76.0 O1,K1,M2,S2 SC Gimcheon 11.0 K1,S2 UC 0.941 0 1.09 0.88 Nakdong Daedeok 70.0 K1,S2 UC River Basin Daegu 10.0 K1,S2 UC 0.994 0 0.98 0.98 Gachang 70.0 K1 ND Daegu 12.0 K1,S2 UC 0.771 0 0.80 0.59 Bisan 70.0 K1,S2 UC Mungyeong 10.0 - ND 0.964 0 0.70 0.92 Nongam 51.0 - ND Mungyeong 15.0 - ND 0.996 0 1.03 0.99 Mungyeong 71.0 - ND Milyang 7.6 - ND 0.524 6 0.14 0.25 Gagok 68.0 K1,S2,M2 SC Milyang 20.0 K1 ND 0.999 0 0.96 0.99 Hanam 70.0 K1 ND Bonghwa 10.8 - ND 0.998 0 0.98 0.99 Myeongho 73.0 - ND Sancheong 10.0 - ND 0.965 0 0.80 0.93 Danseong 70.0 - ND Sangju 10.2 - ND 0.981 0 0.94 0.96 Gongseong 71.0 - ND Seongju 10.0 K1,S2 UC 0.937 0 0.88 0.87 Byeokjin 76.0 K1,S2,M2 SC Andong 10.0 - ND 0.992 0 1.03 0.98 Gilan 70.0 - ND Andong 10.0 K1,S2 UC 0.987 0 1.03 0.97 Taehwa 63.0 K1,S2 UC Table S1. Cont.

Cross-Correlation* Regression* Harmonic Analysis** Watershed Well Station Depth CCF. Time Lag Slope R2 Tidal Effect Aquifer Type Yangsan 10.0 - ND 0.790 0 1.85 0.62 Ungsan 70.0 K1,S2,M2 SC Yeongdeok 15.0 K1,S2 UC 1.000 0 1.00 0.99 Dalsan 70.0 K1,S2 UC Yeongju 13.0 - ND 0.835 0 0.78 0.69 Munjeong 69.0 - ND Yecheon 12.0 K1,S2 UC 0.956 0 0.83 0.91 Yecheon 70.0 K1,S2 UC Ulsan 19.3 - ND 0.991 0 1.02 0.98 Beomseo 79.0 - ND Ulsan 13.5 - ND 0.507 7 0.01 0.17 Sangbuk 80.0 K1 ND Ulsan 9.0 - ND 0.930 0 0.92 0.86 Onyang 70.0 - ND Uljin 15.0 - ND 0.997 0 0.99 0.99 Bukmyeon 70.0 - ND Uiryeong 20.0 K1 ND 0.761 0 0.50 0.57 Nakseo 70.0 K1,O1,S2,M2 SC Uiryeong 9.5 - ND 0.000 0 0.00 0.00 Bongsu 70.0 - ND Uiryeong 15.8 K1 ND 0.947 0 0.87 0.89 Uiryeong 70.0 K1 ND Jinju 12.0 K1,S2 UC 0.979 0 0.89 0.95 Nakdong Chojeon 70.0 K1,S2 UC River Basin Jinhae 12.9 K1 ND 0.976 0 1.29 0.95 Jaeun 35.0 K1,S2 UC Changnyeong 11.5 - ND 0.852 0 0.65 0.72 Seongsan 70.0 - ND Cheongdo 10.5 - ND 0.620 0 0.15 0.38 Cheongdo 70.0 - ND Cheongsong 11.5 - ND 0.905 0 0.86 0.81 Pacheon 68.0 K1,S2 UC Chilgok 10.0 K1,S2 UC 0.991 0 1.10 0.98 Gasan 70.0 K1,S2 UC Chilgok 10.0 - ND 0.992 0 0.86 0.98 Waegwan 70.0 K1 ND Pohang 10.0 K1,S2 UC 0.885 0 0.80 0.78 Gibuk 70.0 K1,S2 UC Pohang 30.0 - ND 0.994 0 1.15 0.98 Yeonil 70.0 - ND Haman 11.0 - ND 0.998 0 0.98 0.99 Chilwon 70.0 - ND Hamyang 19.0 - ND 1.000 0 0.99 0.99 Macheon 70.0 K1 ND Hamyang 10.0 - ND 0.585 0 0.40 0.34 Byeonggok 70.0 K1,S2 UC Hapcheon 16.8 K1 ND 0.998 0 1.06 0.99 Jeokjung 71.0 K1 ND Table S1. Cont.

Cross-Correlation* Regression* Harmonic Analysis** Watershed Well Station Depth CCF. Time Lag Slope R2 Tidal Effect Aquifer Type Nakdong Hapcheon 11.5 - ND 0.949 0 0.85 0.90 River Basin Hapcheon 68.0 - ND Gochang 17.8 S2>M2 SC 1.000 0 0.99 0.99 Seongnae 70.0 S2>M2 SC Gongju 10.0 S2 ND 0.995 0 1.01 0.99 Jeongan 70.0 S2 ND Gunsan 21.0 S2>M2 SC 0.999 0 0.99 0.99 Impi 70.0 S2>M2 SC Geumsan 10.0 K1 ND 0.982 0 1.10 0.96 Geumsan 70.0 K1 ND Geumsan 25.0 K1 ND 0.878 0 0.80 0.77 Boksu 51.0 M2 ND Dangjin 10.0 - ND 0.917 0 1.00 0.83 Sunseong 70.0 K1,S2,M2 SC Daejeon 23.5 K1 ND 0.916 0 1.41 0.84 Munpyeong 72.0 K1,S2 UC Boryeong 12.0 - ND 0.998 0 1.02 0.99 Cheongra 70.0 - ND Boryeong 15.0 K1 ND 0.936 0 0.87 0.87 Cheongso 70.0 K1,S2 UC Boeun 16.5 - ND 0.816 0 0.93 0.66 Maro 70.0 O1,K1,S2,M2 SC Boeun 11.3 K1,S2 UC 0.680 0 0.88 0.11 Boeun 71.0 K1,S2,M2 SC Geum River Buan 15.0 K1,S2 UC 0.999 0 0.97 0.99 Basin Baeksan 70.0 K1,S2 UC Buan 15.0 K1,S2 UC 0.965 0 1.00 0.93 Sangseo 65.0 - ND Buyeo 27.0 K1,M2 ND 0.594 0 0.44 0.35 Buyeo 90.0 - ND Seocheon 17.0 - ND 0.994 0 0.99 0.98 Masan 70.0 K1,S2,M2 SC Asan 11.5 K1,S2,M2 SC 0.979 0 0.90 0.96 Dogo 64.0 K1,S2,M2 SC Asan 12.8 K1,S2 UC 0.646 0 0.53 0.09 Deuksan 70.0 K1,S2 UC Yeongi 15.0 K1,S2 UC 0.793 0 0.83 0.63 Jochiwon 70.0 K1,S2 UC Yeongdong 10.0 K1 ND 0.977 0 0.95 0.95 Yanggang 71.0 K1,S2 UC Yesan 13.8 - ND 0.982 0 1.38 0.96 Deoksan 65.0 - ND Yesan 8.8 - ND 0.986 0 0.97 0.97 Yesan 68.0 - ND Yesan 10.0 K1,S2,M2 SC 0.992 0 1.05 0.98 Oga 70.0 K1,S2,M2 SC Okcheon 7.9 K1 ND 0.670 0 0.45 0.45 Cheongseong 41.0 M2,O1,K1,S2 C Table S1. Cont.

Cross-Correlation* Regression* Harmonic Analysis** Watershed Well Station Depth CCF. Time Lag Slope R2 Tidal Effect Aquifer Type Wanju 15.0 K1 ND 1.000 0 0.99 0.99 Samnye 70.0 K1 ND Wanju 12.0 O1,K1,S2,M2 SC 0.998 0 1.04 0.99 Yongjin 70.0 O1,K1,S2,M2 SC Eumseong 21.2 O1,K1,S2,M2 SC 0.994 0 0.98 0.98 Daeso 68.0 O1,K1,S2,M2 SC Iksan 13.0 O1,K1,S2,M2 SC 0.998 0 1.11 0.99 Nangsa 70.0 O1,K1,S2,M2 SC Jangsu 13.0 K1,S2 UC 0.971 0 1.07 0.94 Jangsu 70.0 K1,S2 UC Jeonju 12.0 K1,S2,M2 SC 0.967 0 1.08 0.93 Manseong 68.0 K1,S2,M2 SC Jeongeup 11.0 - ND 0.961 0 1.00 0.92 Geum River Sintaein 70.0 - ND Basin Jeongeup 13.5 - ND 0.956 0 1.05 0.91 Ongdong 70.0 - ND Jeungpyeong 20.0 K1,S2,M2 SC 0.997 0 1.07 0.99 Jeungpyeong 71.0 K1,S2,M2 SC Cheonan 10.0 - ND 0.940 0 0.85 0.88 Susin 70.0 - ND Cheongwon 25.0 K1,S2 UC 1.000 0 1.00 0.99 Gadeok 65.0 K1,S2 UC Cheongwon 15.4 K1,S2 UC 0.986 0 1.00 0.97 Gangnae 70.0 K1,S2 UC Cheongwon 10.0 K1,S2 UC 0.945 0 1.04 0.89 Buyong 70.0 K1,S2 UC Cheongju 9.2 K1,S2 UC 0.903 0 0.77 0.81 Naedeok 72.0 K1,S2 UC Gangjin 9.8 M2>S2 C 0.976 0 1.20 0.95 Seongjeon 67.0 M2>S2 C Gochang 10.0 - ND 0.990 0 1.02 0.98 Gosu 68.0 - ND Gochang 10.0 - ND 1.000 0 0.97 0.99 Sangha 70.0 - ND Gwangju 10.0 K1,S2,N2 UC 0.996 0 1.01 0.99 Yudeok 70.0 K1>S2>M2 SC Naju 8.5 K1,S2 UC 0.837 -1 0.81 0.68 Yeongsan- Bonghwang 70.0 K1,S2>M2 SC Seomjin Naju 10.4 S2 ND River Basin 0.996 0 0.93 0.99 Samdo 67.0 S2 ND Jangseong 14.0 K1 ND 0.993 0 1.32 0.98 Nammyeon 70.0 K1,S2 UC Jangseong 10.0 - ND 0.988 0 0.87 0.97 Buki 70.0 - ND Jangseong 12.0 K1 ND 1.000 0 1.00 0.99 Hwangryong 64.0 K1 ND Jangheung 11.0 S2 ND 0.973 0 0.84 0.94 Jangheung 64.0 S2 ND Table S1. Cont.

Cross-Correlation * Regression * Harmonic Analysis ** Watershed Well Station Depth CCF. Time Lag Slope R2 Tidal Effect Aquifer Type Hampyeong 12.0 - ND 0.971 0 0.96 0.94 Singwang 70.0 - ND Hwasun 6.4 K1,S2 UC 0.698 2 1.08 0.48 Neungju 62.0 K1 ND Hwasun 10.0 - ND 0.961 0 1.16 0.92 Iyang 70.0 - ND Gangjin 12.0 K1 > S2 > M2 SC 0.995 0 0.97 0.99 Chilryang 66.0 K1 > S2 > M2 SC Gokseong 16.0 K1, S2 UC 0.997 0 0.96 0.99 Godal 70.0 K1, S2 UC Gokseong 8.6 K1 ND 0.984 0 0.93 0.96 Ipmyeon 63.0 K1 ND Namwon 10.0 K1, S2 UC 0.999 0 0.98 0.99 Dotong 60.0 K1 ND Sunchang 12.9 K1, S2 UC 0.969 0 0.94 0.93 Yeongsan- Sunchang 70.0 K1, S2 UC Seomjin Sunchang 16.0 - ND River Basin 0.986 0 0.68 0.97 Ssangchi 70.0 M2 > S2 > K1 C Suncheon 12.0 K1, S2 > M2 SC 0.994 0 0.88 0.98 Oeseo 70.0 K1, S2 > M2 SC Suncheon 10.0 K1, S2 UC 0.998 0 0.98 0.99 Pungdeok 60.0 K1, S2 UC Suncheon 21.0 K1, S2 UC 1.000 0 0.99 0.99 Hwangjeon 70.0 K1, S2 UC Imsil 10.0 K1 ND 0.997 0 0.95 0.99 Deokchi 120.0 K1 ND Jangsu 10.5 K1 ND 0.654 0 0.49 0.42 Sanseo 69.0 K1 ND Hadong 10.7 M2 > S2 > K1 C 0.992 0 1.00 0.98 Hadong 64.0 M2 > S2 > K1 C Hadong 12.0 K1 ND 0.940 0 0.73 0.88 Hwagae 70.0 - ND * Data period: Jan. ~ Dec., 2010, Daily mean data; ** Data period: Feb. ~ Apr., 2010, Hourly interval data; ND: not determined; UC: unconfined aquifer; SC: semi-confined aquifer; C: confined aquifer.