A Visual Mining on RVA Results of Hydrologic Alternations along the East River, South China (1952-2002)

This paper presents a visually-enhanced evaluation of the spatio-temporal patterns of the dam-induced hydrologic alternation in the upper and middle East River, south China during non-flood periods (1952-2002) with the RVA approach and visualization package XmdvTool. Results indicate that: 1) along the East River, dams have greatly altered the natural flow regime, range condition and the spatial variability; 2) the 6 most remarkable indicators of hydrologic alternation induced by dam-construction are the rise rate (1.16), 3-day maximum (0.91), low pulse duration (0.88), January (0.80), July (0.80) and February (0.79) of the East River during 1952-2002; 3) the spatio-temporal hydrologic alternations are different among 3 stations. Under the conjunctive influences of 2 large multi-purpose dams, the rank of the overall degree of hydrologic changes along the middle and upper East River is Lingxia, Heyuan and Longchuan station. The unique approach of integrating spatial, temporal and multi-element hydrological parameters can provide visually-enhanced insights that are not possible with traditional analysis tools into water resources management.