These lesson plans have students observe different portions of topographic maps and try to determine the flow of Mission Creek and all its tributaries. Topographic maps show a 3 dimensional world in 2 dimensions by using contour lines, or equal lines of elevation.  A watershed or drainage basin refers to a system controlled by topography that defines how water will flow. You refer to a watershed by the largest body of water that the creeks, rivers or streams feed into. For example, all creeks that flow in the San Francisco Bay are part of the San Francisco Watershed. However, there are many smaller watersheds within this area depending on flow patterns.  The Mission Creek Watershed would represent all tributaries that flow into Mission Creek.  When Mission Creek divides at Paseo Padre is  the end of the Mission Creek Watershed.  A watershed has an orderly flow pattern. The pattern is dendritic or branching, as it flows from the headwaters to a larger body of water. When one stream flows into a larger stream or river they are called tributaries. The smallest channels in a watershed with no tributaries are called first order streams. A second order stream is when two first order streams join. If you look at the stream order diagram, you can see the creation of a fifth order stream channel. Fifth to sixth order streams are usually larger rivers, while first and second order are often small, steep, or intermittent.

# Defining the Mission Creek Watershed

OBJECTIVES

• Define a watershed.

• Trace and locate places on topographic maps.

MATERIALS

• Copies of 2 sections from Niles Quadrangle  and one from LaCosta Quadrangle Topographic Map

• Student Sheet “Defining the Mission Creek Watershed”

BACKGROUND

What is a watershed? Almost all the area of a watershed is land, not water.  By definition a watershed is the land area from which water, sediment, and dissolved material drain to a common watercourse or body of water.  Did you know that you live on a watershed?  We are fortunate living in Fremont to be able to access and study the Laguna Creek watershed, which is actually part of the larger Coyote Watershed, which includes southern Fremont and parts of Santa Clara County (delineated by U.S. Geological Survey).  When studying watersheds, it is important to understand all of the factors which effect the watershed system.  Factors include climate, physical features, soil, geology and vegetative cover.

In this unit, students will study and trace the path of Mission Creek and locate other places on a section of the Niles and LaCosta Quadrangles from the U.S. Geological Survey.

PROCEDURE

Students should use the sections copied from  U.S. Geological Survey 7.5 minute quadrangles and answer the questions on the worksheet.  If students are unfamiliar with the symbols used on the map, please refer to our lesson online on “Map Reading” and “Maps as a Tool.”  You can find them by using the following url:  http://msnucleus.org/membership/html/jh/earth/index.html