Studies on ecological water level of Dongping Lake
The Mann-Kendall method,moving t-test technique,and wavelet analysis were used to de-termine the water level mutation point of Dongping Lake,analyze the trend of the annual average water level change,and characterize the daily water level change based on the daily water level sequence of Dongping Lake from 1960 to 2020.The impact of water level change on the spatial evolution of Dong-ping Lake wetland was discussed.The ecological water level of Dongping Lake was studied using the annual spreading method and the variability range method(RVA)in combination.The results showed that(1)the abrupt change of water level occurred in 1989,and the rise of the water level has caused a significant evolution in the wetland space at the entrance and exit of Dongping Lake;(2)the monthly ecological water levels calculated with the annual spreading methods 1 and 2 before the water level mu-tation varied between 38.11 and 39.46 m and between 36.94 and 38.24 m,respectively,the monthly protection degree of the ecological water level before the mutation was relatively high,and the water level remained high for a long time after the water level mutation;(3)the ecological water level of Dongping Lake was calculated based on the water level sequence after the abrupt change,the monthly ecological water level calculated by the annual spreading methods 1 and 2 within the year ranged from 39.83 to 40.55 m and from 37.59 to 38.27 m,and the duration of high and low water levels varies greatly in different years;(4)the ecological water level of Dongping Lake calculated with annual spreading method 1 during the year ensured that the wetland will not degrade,at the same time,by combining the underwater elevation of the wetland with the growth period of the reeds,the suitable wa-ter level of Dongping Lake can be determined;(5)by setting the dynamic water level of the Dongping Lake flood limit,the Dawen River flood can be resourced and the health of Dongping Lake ecosystem can be guaranteed.
Dongping Lakewater level mutationwetlandsannual spreading methodecological wa-ter levelsuitable water level
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