An assessment of the surface water resource potential of New Jersey, USA.

摘要

New Jersey is one of the most populous states in the United States. The steady growth in population coupled with regional shifts in population places enormous additional demand on the states' water supply especially in times of drought. This research describes techniques for assessing the surface water potential of New Jersey, USA in times of drought. The analysis employs methods commonly used to assess surface water availability potential using unregulated streamflow data. Performance indices have been used to assess the spatial distribution of stream performance during drought in order to delineate potential "promising" or "stressed" areas. Furthermore, frequency and risk of drought events with differing magnitude, duration, and intensity that have occurred in the state since the last century have been determined. Besides, the effect of the impact of climate change and land use change on lowflow in the six main drought regions of the state has been investigated.;Results from the research revealed that streams that drain northern catchments have higher carryover capacity in comparison to their southern counterparts. Thus, the water holding capacity of northern watersheds from one time period to the next is comparatively higher than watersheds in the south. Though groundwater recharge to streams in southern New Jersey is generally higher than their northern counterparts, it appears relatively less groundwater release from storage in any given (present) year in the south is carried from the previous year(s). An examination of the performance metrics also showed that drought in southern catchments could be less severe than those in the north even though drought in the south could be long-lived. The worst historical drought on record (1961--1967) since the last century has a return period on the order of 2000 years and the risk that such a 7-year drought will occur in a 25-year period is less than 1%. In addition, the return period of the most severe single year drought on record (drought of 1985) is about 250 years and the risk that such a one-year drought will occur in a 25-year period is about 6.7%.;Results of the sensitivity of climate and land use change on lowflow indicated that, land use change does not heavily impact lowflow as does climate change. Further, it appears that when land use change impact on a watershed, a 1% change in land use results in less than 0.5% change on lowflow. The spatial distribution of land use change on lowflow revealed that lowflow in southern watersheds is more sensitive to land use change compared to northern watersheds. This can be attributed to the fact that recharge to southern streams is mainly from groundwater (in comparison to the northern streams). Thus a change in land use change for southern watersheds will change lowflow to a greater degree than northern watersheds. This observation implies that streams (i.e., lowflow) in the southern portions of the state have a high propensity of being threatened during drought as a result of future increases in population. The study further indicated that watersheds with average impervious cover reaching at least 5% may have the tendencies of exhibiting reduction in lowflow.