Impacts to the hydrology of the Cache River, a major river system in the Mississippi Alluvial Valley, were assessed by integrating hydrologic analyses with a review of historical land use changes. Extreme low flows have become more frequent in recent years, coincident with a dramatic increase in rice farming in the basin and its associated irrigation, Annual drawdowns in the alluvial aquifer were positively correlated with the annual area of rice crops. There is no evidence that a change in climatic conditions accounts for the increase in extreme low flow frequency. In fact, multiple regression analyses indicate the relationship between ctimate and flow is weakest in more recent decades when extreme low flows were more prevalent. Low flows in the summer (when rice irrigation occurs) were least associated with climate in most recent decades.Average monthly flows t-or August and September have increased, which is also an impact consistent with rice agriculture practices. Water is drained from rice fields to surface-water drainages at the end of the summer and may eventually reach the Cache River, thus increasing late summer flows. The timing and nature of changes in agricultural practices within the Cache River basin suggest agricultural impacts have contributed to the observed changes in hydrology.

The purpose of this technical note is to provide guidelines on the use of conceptual models to improve system-wide planning and operation of water resource projects of the Corps of Engineers. Conceptual models provide a tool to represent, communicate, and analyze the structure, functions, and hierarchical relationships of the systems affected by Corps activities. The movement toward ecosystem restoration projects and toward sustainability of economic and ecologically viable systems has brought into focus the need to approach some Corps activities on a system-wide basis including: • Understanding the response of natural resources to environmental change or stress. • Supplying reliable services, e.g., flood damage reduction, maintenance of biodiversity. • Designing and managing projects in a sustainable manner.

To sense and experience the environment firsthand has profound educational and motivational value. The splendor of the Rocky Mountains lures one to explore, and with this adventure comes an opportunity to learn lessons in ecology in a way very different from the traditional classroom approach. To climb a high mountain is to witness the transition that occurs in biological communities with a change in climate. The same observations on the horizontal would require traveling thousands of miles.Our national parks are valuable educational resources and can serve as outdoor laboratories. Two of these parks, Glacier National Park and Rocky Mountain National Park, were used in an ecology travel study program. In this course, students discovered the life zones of the Rocky Mountains and how the mountains, in turn, influence life zones for hundreds of miles east across North America.This paper describes the use of a field trip to the Rocky Mountains to promote knowledge, understanding and awareness of the environment. It discusses some ecosystems encountered on the trip and describes some of the hikes taken in these parks. It is not the intent of this paper to give a detailed account of these ecological communities, but rather a general idea of the educational potential of the course with some direction to the educator for planning.

No abstract