Faster boats speeding rate of shoreline erosion

Why do people armor shores with rocks or walls? It does remove ecosystems. (See "Living on the Edge," July-August 2007.)

People armor because shores are eroding. These are shores where deposition balanced erosion for centuries.

Erosion removes ecosystems too: We lose land and wetlands, as well as add tons of sediment to the Bay.

Why is there more erosion now than in past generations? Water levels have not risen much yet, and erosion has grown even on undeveloped shores.

The biggest change is a vast increase in the number and speed of speedboats. A Maryland General Assembly study done in 1978-80 measured erosion and erosive forces from boats of different sizes and speeds (See Zabawa et al. at

Other studies around the world confirm a range of .001 to .008 inches eroded each time a speedboat goes within a few hundred feet of shore.

Multiply by the distances boats travel on a gallon of fuel, and this sliver of erosion works out to an average of seven or more square feet lost per gallon of fuel burned.

Energy in boats' fuel largely goes into making wakes. The wakes' energy is dissipated on shores, eroding them and putting sediment in the Bay.

This conservation of energy is why there is a direct relation between fuel burned and land eroded.

Floods and storms also erode, but then they leave sediment on high ground, completing the same balanced cycle we have had for millennia.

Boat wakes do not raise sediment on land, so they just erode, making the Bay and its tributaries wider, shallower and murkier.

Are speedboats in the Bay model? Will they share in sediment reductions needed by 2010? Or will we continue to armor?

Paul Burke
Shepherdstown, WV

It's not a matter of how long but how much we will sacrifice for Bay

The streams of Lancaster County of Pennsylvania have been my playground and classroom since I was 6 years old.

I was fortunate to have parents who taught awareness of and admiration for the wonders of nature, and my curiosity grew with each discovery beneath a rock or among the reeds.

It is sad that curiosity and the thirst to learn are waning in our world today because everyone seems to be looking for "the quick fix."

Many communities-including my own-heavily impact the Bay yet are not fully aware of its endangered state or how to help remedy it. Many, if asked to provide a solution to stream bank erosion, for example, would suggest planting trees along the bank because they think it is a quick, cost-efficient way to hold soil in place.

What they may not realize is that if a stream bank is too high or unstable, the trees' roots cannot reach the groundwater to remove nutrients or that the tree could be swept away during the next storm.

The ecosystems that make up the Chesapeake Bay are just as fragile as the health of the streams that impact it. The article, "Plan to harvest cownose rays could be recipe for trouble" (July-August 2007), highlight the impact of cownose rays on oyster survival.

I believe it is short-sighted-not to mention selfish-to introduce a ray fishery just to increase the oyster harvest.

Focusing on a successful method for oyster reintroduction will to be straying from the goal of reviving the Chesapeake's brittle health if it does not also address improving the habitat for the hundreds of other organisms sharing the ecosystem.

We are on a time clock and its not stopping, no matter how many quick fixes we shove in its way. It is not a question of how long the Bay's restoration will take.

The issue facing the Bay is and always has been how much we are willing to sacrifice to save it.

Claudia Shuman
Pequea, PA