Assessment of Long-Term Salinity Changes in an Irrigated Stream-Aquifer System
Assessment of Long-Term Salinity Changes in an Irrigated Stream-Aquifer System
复制标题
灌溉溪流含水层系统中长期盐度变化的评估
DOI：
10.1029/wr021i011p01611
复制
发表时间：
1985
影响因子：
5.4
通讯作者：
M. Person
中科院分区：
文献类型：
--
作者：
L. Konikow;M. Person
科罗拉多东南部的阿肯色州河谷地下水和地表水的盐度变化主要与灌溉措施有关。溶质运移模型被应用到一个11英里的河段的山谷，计算盐度变化的空间和时间变化的应力。1973年，利用1971年和1972年期间进行的详细实地测量对模型进行了校准。1973年，校准模型被用于预测，如果观测到的灌溉做法继续下去，地下水盐度将逐渐增加，每年约增加2-3%。1982年冬季对研究区域进行了重新采样，以帮助评估盐度是否确实发生了长期变化。非参数和参数统计检验被用来帮助评估所观察到的地下水盐度变化的意义。这些测试表明，在1971年和1972年的冬季（模型校准期）之间，盐度出现了统计学上的显著增加。然而，1972年冬季和1982年冬季数据的比较表明，在这10年期间，盐度没有发生重大的净变化。少数可用的历史数据（1895年，1923年，1959年至1961年，和1964年）的分析支持的假设，在这个灌溉区的地下水盐度已达到长期动态平衡的灌溉实践。长期盐度增加的模型预测是无效的，可能是因为校准期间发生在河流（因此在渗漏灌溉渠和应用灌溉水）中盐度增加的短期年度趋势期间，这并不代表长期趋势。
Changes in salinity in groundwater and surface water in the Arkansas River valley of southeastern Colorado are primarily related to irrigation practices. A solute transport model was applied to an 11-mile reach of the valley to compute salinity changes in response to spatially and temporally varying stresses. The model was calibrated in 1973 using detailed field measurements made during 1971 and 1972. In 1973 the calibrated model was used to predict that a gradual long-term increase in groundwater salinity of about 2–3% per year would occur if the observed irrigation practices continued. The study area was resampled during the winter of 1982 to help evaluate if any long-term changes in salinity are actually occurring. Nonparametric and parametric statistical tests were used to help assess the significance of observed changes in groundwater salinity. These tests indicate that a statistically significant increase in salinity occurred between the winters of 1971 and 1972 (the model calibration period). However, a comparison of the winter 1972 and winter 1982 data indicates that no significant net change in salinity has occurred during this 10-year period. An analysis of the few available historical data (1895, 1923, 1959–1961, and 1964) supports the hypothesis that groundwater salinity in this irrigated area has reached a long-term dynamic equilibrium in response to irrigation practices. The model predictions of long-term salinity increases were invalid probably because the calibration period occurred during a short-term annual trend of increasing salinity in the river (and hence in leaky irrigation canals and in applied irrigation water), which was not representative of the long-term trend.