Importance of infiltration -water infiltrates into the soil - It continues to move vertically down through the soil profile -it is treated by the soil (cleans out impurities) -it joins with the local groundwater -enhancing the quantity of groundwater available for local use.
Factors that influence how much rainfall will runoff and how much will infiltrate into the ground:. 1. The topography 2. The size of the watershed 3. The type of land cover
Topography Definition-the features (such as mountains and rivers) in an area of land The topography and elevation of the watershed will impact the speed in which runoff will reach the lake. The steeper the watershed land area, the faster the runoff
The size. The greater the amount of land area in a watershed the more opportunities for runoff to reach the lake, river, or ocean via streams.
Type of land cover.Watersheds covered in vegetation and forests provide a chance for rainfall to be absorbed by plants and filtered into the ground. Watersheds covered in hard or impervious surfaces cause the rainfall to runoff more rapidly because there is no plant material to stop and absorb the flow of water.
Topographic Map Shows relief using contour lines -Relief – highs and lows of Earth’s surface Relief can be calculated 1. Take the difference between the highest point an the lowest. (ex. Mountain peak- 20m lake = 10 m 20m – 10m = 10m The relief of this area is 10m
Reading a topographic map-Contour Lines Contour lines -Lines on topographic maps -Connect points of equal elevation. Everything connected to that line has the same elevation Elevation – the distance something is above sea level. (sea level = 0m or 0 ft.)
Use of Topographic maps with watershed studies Topographic maps are used to show the direction of waterflow over a watershed.
Slope direction is calculated perpendicular to the contour lines...so the direction of flow is always perpendicular to the contour lines
Point source pollution Water pollution that comes from a single, discrete place, typically a pipe.
Nonpoint source pollution As water from rainfall and snowmelt flows over and through the landscape, it picks up and carries contaminants from many different sources.
What are some types of nonpoint pollution? http://protectingwater.com/index.html
– Lower water depths during non-storm periods – Higher than normal water levels during wet weather periods – Increased sediment loads – Higher water temperatures – Native fish and other aquatic life are stressed by run off
Conserve water – inside and out Do not fertilize your lawn before a rain storm or over-fertilize it so that the excess runs off into the streets Take your car to a car wash where the water is treated and recycled. Do not pour anything down your storm drain Look for alternative forms of transportation, i.e.car pool, public transportation, bike, etc.
Clean up after your pets Smart waste disposal, i.e. recycling, using proper receptacles to dispose of waste and hazardous waste, i.e. car batteries, solvents, pesticides, etc. Become involved, join your local watershed group or volunteer monitoring organization Get informed, learn all you can about your local watershed and about NPS pollution, with knowledge, we can make a difference