Date of Award

8-2016

Level of Access Assigned by Author

Campus-Only Thesis

Degree Name

Master of Science (MS)

Department

Civil Engineering

Advisor

Shaleen Jain

Second Committee Member

Stephen Norton

Third Committee Member

David Courtemanch

Abstract

Sustainable water resources allocation seeks to balance the growing consumptive freshwater needs with appropriate resources to support aquatic ecosystems. By placing limits on water withdrawals and ensuring instream flows to support riverine ecosystems, a number of new approaches are seeking to develop a scientific basis for water allocation rules and policies. In this regard, new knowledge stemming from "Natural Flow Regime” paradigm offers a promising first-step for use of quantitative flow-based metrics for ecological flow appropriations in streams. One concern that has compounded the challenge linked to sustainable water resources management is that of a variable and changing climate. In particular, changing hydrologic baselines (for example, stemming from shifts in the seasonality and magnitude of streamflow) render flow policy or rules ineffective over time. This study is motivated by the above noted concerns, and uses state of Maine’s "Instream Water Flow Policy (Chapter 587)" as a case study and investigate the nature of variability and change in the streamflow over the past half-century. Furthermore, analyses based of watershed chemistry records and hydrologic modeling are pursued to understand the interlinkages between hydrologic and geochemical fluxes. Finally, a case study involving hydrologic modeling with limited data and considerable uncertainty investigates the issues related to use of models for water resources decision-making.

The major findings of research presented here are:

1. Analysis of historical daily streamflow records for 31 streams in the New England region reveal systematic shifts in the seasonal cycle of streamflow with three characteristic features: (a) the seasonal contribution of flow has spatial variability as the region comprises a prevailing Spring flow season in the northern region with a dominant winter flow season from central to southern region, (b) early snowmelt-driven increases in spring flows, followed by longer low flow period in late spring and early summer, (c) these changes are significantly impacting the natural variability in streamflow in terms of the streamflow indices.

2. Assessments of Chapter 587 based on range of variability approach under the above changing hydrologic scenarios demonstrate major distress over the policy implementation with a changing baseline condition.

3. Development and uncertainty analysis of hydrologic model aid in understanding critical issues with decision making while implementing water policy in a changing climate.

4. Exploration of interlinkages between chemical fluxes with streamflow will aid in using alternatives to hydrologic models where rainfall or temperature gauge stations are insufficient.

The prime goal of the research is to ease the critical understanding of the stand of Maine state water allocation policy (Chapter-587) for future uncertainty and better help to investigate and analyze the critical aspects of watershed in an insightful way.

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