Tides of the Delaware EarthCache
-
Difficulty:
-
-
Terrain:
-
Size: 
(other)
Please note Use of geocaching.com services is subject to the terms and conditions
in our disclaimer.
Tides of the Delaware Earthcache
Formation of a river.
Geologically, the Delaware River was formed as a result of the retreat of the Wisconsin Glacier which began 20,000 years ago. As the large sheet of ice melted and receded, it carved and sculpted the landscape. The present day Delaware river is cut through a silt and sand terrace.
The Delaware River is a major river on the Atlantic coast of the United States. Including New York, where it begins, the river flows 419 miles (674 km) through the States of Pennsylvania, New Jersey and Delaware where it empties into the Atlantic Ocean. The river's watershed (area of land where all of the water that is under it or drains off of it goes into the same place) drains an area of 14,119 square miles (36,570 km2) in the four aforementioned states.
A tidal river.
A tidal river is a river, or more typically a stretch of a river, whose flow and level is influenced by tides. As the Delaware river is connected to a coastal ocean, this subjects it to ocean influences including tides. Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun and the rotation of the Earth. As the tides in the Atlantic Ocean rise and fall it affects the levels of the water of adjoining rivers, such as the Delaware River.
Types of tides.
Locations which experience two almost equal high tides and two low tides each day is called a semi-diurnal tide. Locations which experience only one high and one low tide each day is called a diurnal tide. Locations which experience two uneven tides a day, or sometimes one high and one low each day is called a mixed tide.
Tide gauges are used to measure the water level over time. At Philadelphia, tide gauge measurements of the Delaware river have shown water level shifts of nearly 7 feet. Actual tide measurements at Philadelphia for March 13, 2013 are shown below (source: NOAA.org).
In order to log this Earthcache, you must email team wiji (see profile for email) the answers to the following questions:
1. At the posted coordinates, you will be standing at the end of Race Street Pier, which provides a great view of the Delaware River. The water level is affected both by how much water enters river via the watershed and the tidal action. Estimate the distance from where you are standing to the water surface? (This can be estimated by counting the number of 'bricks' which make up the support pillar of the Benjamin Franklin bridge to your left.)
2. Based on the information presented, does the Delaware River experience a semi-diurnal tide, diurnal tide, or mixed tide?
3. Observe the speed and direction of the river flow. Would you consider this a fast-moving or slow-moving river? Secondly, which direction (ie. North, South, East, or West) is the water flowing? Look closely, the direction will depend on the time of day you visit this tidal river!
4. OPTIONAL - Take a photo of your GPSr or yourself/team with the Delaware River in the background. You may include this photo in your log.
++ Congratulations to Groundhog25 on the FTF!! ++
Additional Hints
(No hints available.)