The Upper Mississippi River System (UMRS) is a large and diverse river system that changes character along its 1,200 mile network of rivers and canals and 2.6 million acres of floodplain. It supports more than 30 million people in its watershed, a significant commercial waterway, more than a million acres of ''floodplain'' agriculture and about one-half million acres of river-floodplain managed for fish, wildlife, and recreation. Large-scale geomorphology and climate patterns largely determine the hydrologic characteristics of a nested hierarchy of UMRS river reaches. The human impacts above are also important drivers determining hydrologic characteristics within the hierarchy. Understanding the relationship among physical and chemical processes and ecological responses is critical to implement an adaptive management framework for UMRS ecosystem sustainability. Historic or contemporary data from 42 locations were used to examine changes in UMRS hydrology and to demonstrate the utility of a multiple reference condition analysis for river restoration. A multivariate mathematical framework was used to show how river stage hydrology can be characterized by the variability, predictability, seasonality, and rate of change. Large-scale ''geomorphic reaches'' have distinct hydrologic characteristics and response to development throughout the UMRS region, but within navigation pool hydrology is similar among all impounded reaches regardless of geomorphic reach. Reaches with hydrologic characteristics similar to historic reference conditions should be examined to determine whether those characteristics support desired management objectives. Water levels can be managed, within limits to support navigation and agriculture, to more closely resemble natural hydrology for the benefit of a variety of species, habitats, and ecological processes.

Ecosystem restoration planning requires quantitative rigor to evaluate alternatives, define end states, report progress and perform environmental benefits analysis (EBA). Unfortunately, existing planning frameworks are, at best, semi-quantitative. In this paper, we: (1) describe a quantitative restoration planning approach based on a comprehensive, but simple mathematical framework that can be used to effectively apply knowledge and evaluate alternatives, (2) use the approach to derive a simple but precisely defined lexicon based on the reference condition concept and allied terms and (3) illustrate the approach with an example from the Upper Mississippi River System (UMRS) using hydrologic indicators. The approach supports the development of a scaleable restoration strategy that, in theory, can be expanded to ecosystem characteristics such as hydraulics, geomorphology, habitat and biodiversity. We identify three reference condition types, best achievable condition (A BAC ), measured magnitude (MM i which can be determined at one or many times and places) and desired future condition (A DFC ) that, when used with the mathematical framework, provide a complete system of accounts useful for goal-oriented system-level management and restoration. Published in

Upper Mississippi River ecological integrity has been severely compromised by human activity during the last 50 years. In response to the continuing decline of natural resource values, two approaches for protecting and improving the Upper Mississippi River-floodplain ecosystem have been used. Habitat rehabilitation and enhancement projects are being constructed at 54 locations to provide site-specific rehabilitation. The projects are designed to counteract the adverse ecological effects of sedimentation through (1) flow introductions, (2) the isolation of backwaters; and (3) flow diversions and wave breaks. Channel maintenance projects are being re-evaluated in an attempt to construct or modify existing river training structures that are environmentally sympathetic. The latter approach works with the river's energy, whereas the former attempts to overcome riverine processes. Both approaches have significant limitations because they affect limited areas. A proposal is presented that restores some ecosystem integrity by re-establishing occasional low river stages that occurred before the implementation of the Upper Mississippi River Navigation System.

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Upper Mississippi River Restoration (UMRR) was implemented to monitor environmental status and trends and restore degraded habitat. There was little experience conducting restoration in large rivers, and engineering and ecological integration evolved through project implementation. Loss of depth in backwaters and side channels, excessive biological oxygen demand, increased currents, and low water temperatures were common symptoms of backwater eutrophication that were primary objectives for implementing UMRR. Biological outcome monitoring was initially funded for six projects using the most common methods to restore aquatic and wetland habitat. UMRR island construction occurred as four generations of learning. Current plans represent a comprehensive restoration approach including: physical process modeling (i.e. hydraulic and wind-wave modeling) of existing conditions and alternative restoration measures. Habitat Rehabilitation and Enhancement Projects, fish response monitoring validated winter habitat suitability models. Long term fish population monitoring indicates sustainable recovery, and now population interaction among restored lakes is under investigation. Isolated wetland management in Illinois River backwater lakes can achieve bottom consolidation that promotes emergent wetland habitat response that migratory waterfowl exploit in large numbers. Adult fish movement between the river and management units is restricted to flood stage or through control structures and post-project movements into the lake for overwintering were not apparent. The lack of Illinois River overwintering habitat is shown by an abundance of young fish and few older fish in status and trends monitoring. Upper Mississippi River System ecosystem restoration practitioners have implemented ecosystem restoration science and practice in a manner that exemplifies the best intent of adaptive management.