onment for the rest, has within the past few years been killing
off one by one all the special satisfactions and delights that cities
from time immemorial have furnished their inhabitants.

[Illustration:

This 26 square-mile section of the Rock Creek watershed, just above the
District line in Maryland, was rural in 1913, with many small
tributaries fed by springs and seeps. Ensuing development based on
little knowledge of natural processes covered most of the old aquifer
recharge areas with pavements and rooftops, so that more precipitation
ran rapidly off the land instead of soaking in and flowing out gradually
into streams. Flooding during storms and loss of flow at other times
caused most of the tributaries to be covered over as storm sewers, so
that out of 64 miles of natural flowing stream channels that existed in
1913 in this section, only 27 miles can be found above ground today.]

Fleeing the dissonant center--or avoiding it from the start when they
move to the metropolis from elsewhere--citizens who can afford it move
into suburbs carved in the outlying countryside by gargantuan machinery,
sometimes in compliance with a plan that preserves some trees and airy
open space and a sense of the things that were, but more usually not.
Here the fugitives place themselves one against the other in the
hugeness of their numbers so that very quickly in many places the
countryside hardly exists except in leapfrogged forlorn patches or
farther out, where its ownership in speculatively held blocks--the old
farm houses gone to pot, their fields in weeds or casually tilled or
grazed to merit agricultural taxation--avouches the certainty of
continuing sprawl. It is a much-documented process with two decades of
history behind it now. It is cancerlike in its effect on the region, and
disillusioning in its effect on many of those who participate, for
often it forces them into the position of being mass destroyers of the
very things they seek--air and wild greenery, quietness and the elbow
room to be themselves.

[Illustration]

A growing body of knowledge as to what kind of terrain can stand dense
development, and what kind cannot, and how streams and woods and
wildlife and even farms can be physically retained among urban
populations, and why they ought to be, is becoming available. Its
principles are more or less ecological, which simply means that they
seek to maintain right uses of different elements of the landscape unde