Assignments for Class 3: Rivers and Watersheds of Virginia
southern Fairfax County/northern Prince William County, from I-66 to Lake Montclair
(can you spot Lake Barcroft, Burke Lake, Occoquan Reservoir, Lake Manaassas, or Mason Neck? Compare your answers with an image listing those places
Source: NASA - Stennis Space Center
- You should be participating now in the blog on Blackboard, by adding your "comment" to my posts. There's a post on the blog where you should add a commebnt to introduce yourself, and a second post about dinosaurs in Gainesville.
- Build on what we have learned so far:
- - read Virginia Earthquakes
- - read about the August 23, 2011 Earthquake
- - if geology intrigues you, you can follow the Virginia Department of Mines, Minerals and Energy - Division of Geology and Mineral Resources on Twitter now, at http://twitter.com/#!/VAGEOL
- - use the DeLorme Atlas and Gazetteer to find places we discuss in this class, so you'll be prepared for a quiz question such as what two major highways go through Cuckoo? (Cuckoo is also famous as the starting point for Jack Jouett's 40-mile ride in 1781 to warn The governor, Thomas Jefferson, and other officials that "the British are coming." Jouett's journey could have become as famous as Paul Revere's ride from Boston in 1776, but no poet as skilled as Henry Wadsworth Longfellow has tackled the topic - yet. Read about it at Midnight rider: How Jack Jouett saved Virginia.)
Virginia watersheds (do any Virginia rivers drain into Tennessee, Kentucky, or West Virginia?)
1) Class Lecture Material
- - Watershed and Divides (get very clear on the relationship between ridges that separate watersheds and the path of rivers themselves - on a map, watersheds are large areas while rivers are thin blue lines)
- - Hydrologic Units of Virginia
(If you keep subdividing the large watersheds into smaller and smaller sub-watersheds... this is where you stop)
Sixth Order Hydrologic Units, as defined by the 12-Digit National Watershed Boundary Dataset for Virginia
Source: Virginia Department on Environmental Quality
- - Watersheds of George Mason University
- (when you enter the zip code for GMU (22030) in EPA's Surf Your Watershed tool and click "go" - why does it list more than one watershed in response?)
- - So Why Do We Care About Watersheds and Divides?
- - Rivers and Watersheds
- - Find the "Big Four" Rivers of the Coastal Plain
- - We interrupt this program...
"layers" displayed on this map include topography, rivers and waterbodies,
and political boundaries - but no roads are displayed
- - The Fifth River
- - look closely at the white line defining the watershed boundary of the Chesapeake Bay, in the full-size version of the Chesapeake Bay watershed poster
- - be sure to look at the topographic/bathymetric map of the bay area
- - Why are the river mouths wider?
Rivers in far southwestern Virginia located west of the Eastern Continental Divide will drain to the Gulf of Mexico, not directly to the Atlantic Ocean. (The Eastern Continental Divide is located in three physiographic provinces - clearly the physiographic province boundaries are not based on watershed boundaries...)
- - Lake Drummond
- - Mountain Lake
- - Caves and Springs in Virginia
- - Introduction to Virginia's Karst
- - A Reference Guide for Landowners in Limestone Regions
- Why Karst Protection?
- Pollution and Protection of Karst Wells and Springs
- - Living With Sinkholes
- - Virginia Department of Mines, Minerals and Energy - Sinkholes and Karst Terrain
southeast Virginia, showing Lake Drummond and Union Camp holding ponds to west (at Franklin)
Source: NASA - Stennis Space Center
- - watershed boundaries of the Chesapeake Bay as defined with a white line on the image (does all the rain that falls on the City of Virginia Beach - the whole city, all 248 square miles, not just the sandy resort beach area - drain into the Chesapeake Bay?)
- - watersheds from William and Mary (if you spill a soda while watching UVA play Virginia Tech in a football game at Scott Stadium in Charlottesville, where will the water from the melting ice end up going? if you spill a soda at Lane Stadium in Blacksburg... will the melted ice end up draining to the same place?)
- - drainage basins of Virginia from William and Mary (will a soda spilled at James Madison University in Harrisonburg end up flowing over Great Falls, upstream of Washington DC?)
if you drive on I-81, you'll cross the watershed divide between the James/Shenandoah rivers at the exit for Raphine/Steele's Tavern
Source: National Atlas
- - Virginia's Major Watersheds (If you are so clumsy that you spill yet another drink while wandering through downtown Roanoke, will the melting ice end up in the Chesapeake Bay? And did you note the small watershed at the southern corners of Carroll and Patrick counties? It drains into the Yadkin River of North Carolina, then into the Pee Dee River of South Carolina, and ultimately the Atlantic Ocean. Rain can fall east of the Blue Ridge and not run into either the Chesapeake Bay *or* into Albemarle/Pamlico Sound. WARNING: the previous two depictions of Virginia watersheds ignored the Yadkin/Pee Dee segment...)
- - Virginia hydrography (look carefully at the rivers in Southwest Virginia. Follow the blue lines... do they all connect with the Chesapeake Bay, or do some disappear across the state line into West Virginia and Tenessee? Do any go into Kentucky? The three main watersheds in Southwest Virginia drain into the Ohio River, so they are not tributaries to the Chesapeake Bay. Their fourth order USGS HUC code will not start with 02...)
watershed divide at the headwaters of the Shenandoah River
(arrows show the direction of the flow of the water - downhill, of course, but in different directions -
so think of the watershed divide as the tip of the roof separating the Shenandoah River on the north from the James River on the south)
Source: National Atlas
- - How Much of Virginia is Water?
- - Chesapeake Bay Geology and Sea Level Rise (maybe more of Virginia will be water rather than land?)
- - Refresher: So What's a "Watershed"? (ya really gotta learn this copncept, in order to understand the political debate over the Chesapeake Bay cleanup, and why Representative Bob Goodlatte from the 6th District is trying to block funding of the Environmental Protection Agency's program to implement mandatory limits on pollution going downstream from Goodlatte's Shenandoah Valley to the bay)
- - How Watersheds Define the Boundaries of Virginia (observe how the divide along the Blue Ridge was used to define natural boundaries for counties, similar to the way the Fairfax Grant's southern edge was based on the Rapidan and Rappahannock Rivers)
- - "The Northern Neck" Is Not "The Peninsula" (be sure you understand Tidewater jargon, and could label the rivers and "necks" along the bay if you saw this sort of map on a quiz)
- - Virginia’s Most Pristine Water Body
- - So, How Does That Sewage Taste?
parcel boundaries, showing fragmented ownership in Dragon Run watershed, complicating conservation efforts
(buildout analysis based on comprehensive plans showed almost 40,000 houses or other structures could be built on those parcels)
Source: Dragon Run Management Framework
Use the Geographic Names Information System (GNIS), which you also used in Week 1. This time, find how many places in Virginia are identified as "lakes." (Remember from your readings this week how many natural lakes are in Virginia, so the results of this GNIS query are a clue regarding how many non-natural lakes have been created and how much human settlement has transformed the landscape...
search GNIS for features
in Virginia called "lakes"
Trace the Bay using the DeLorme Virginia Atlas & Gazetteer. Get familiar with the political jurisdictions that have Chesapeake Bay shoreline in Virginia, as well as the brigdes/tunnels in Hampton Roads.
- watch What is a Watershed (co-produced by EPA and The Weather Channel)
- watch "Travels Around George Mason University" on GMU-TV streaming video. Note that the website address for the class has changed since this segment was recorded. Also, remember that the antipode of the Fairfax Campus of GMU will be a location in the Southern Hemisphere, at roughly 39 degrees south of the equator. (My high tech geo-locator globe used in the video distracted me; the antipode is not 51 degrees south of the equator. The Antipodes Map is correct, while my statement in the video is... wrong. Duh. My bad.)
Choose a stream near where you currently live or work. Be prepared for a greater challenge if you live/work in a highly-developed urban area, where major portions of the streams have been paved over and converted into storm sewers.
- For the field trip report, observe and report on the following:
- - what is the name of your stream, and where did you choose to observe it? (If you don''t know its name, what name would you suggest would be appropriate for that stream, and why did you pick that name?)
- - from the banks of the stream (or the bridge), determine what direction is upstream
- - where is a watershed divide for your stream? If walking or driving in a certain direction, where would you say you had "crossed the divide" and entered the "headwaters" of another stream?
- - what is the name of the stream on the other side of your watershed divide? (Remember, the "headwaters"of a stream is at the opposite end from the mouth of the stream. The headwaters will be at the highest location in that portion of the stream's watershed. For example, the furthest uphill headwaters of the Potomac River is marked by the Fairfax Stone in West Virginia, while the mouth is where the Potomac River enters the Chesapeake Bay.)
- - do the sides of the stream (the "banks") and the bottom on the stream (the "bed") appear natural with green vegetation and minnows swimming in the pools of water, or has the stream been changed (degraded) extensively by human development? if so, what development had the greatest impact?
- - are there any obvious environmental protections, such as protected buffer strips of vegetation, along the stream? Are there stormwater ponds, low dams, or other "built/engineered" controls that might reduce flood damage?
- - do you think the runoff from a September rainstorm will be filtered and slowed to a gradual seepage before entering the stream, or will the rainfall rush almost immediately into the stream and stimulate a quick rise in water level downstream?
- - what might be affected downstream by increased water levels? would a flash flood cover a greenway, soccer field, or parking lot... or are there buildings occupied by people, located right on the edge of the streambank?
- - how could a potential homeowner, looking at a house near a creek, discover the risk of a flood at that location?
- - based on what you know about your stream, you could articulate an informed opinion: should new buildings be permitted in the area that will flood so long as the owners are willing to buy flood insurance, or should the government define a boundary where no development should occur?
Great Falls of the Potomac River after heavy rainfall in September, 2011
(the waterfalls are located primarily in what state?)
Syllabus and Class Schedule