56:
Before the twentieth century, the
Conejohela Valley was a marshy floodplain, with extensive wetlands. The Susquehanna River flooded annually in the spring, and there were more damaging floods approximately once per decade. Thick forests surrounded a mixture of small waterfalls, rapids, and marshes. A
81:
was built, once believed to be the longest covered bridges in the world. It was replaced by bridges built of structural steel, large enough to carry a range of vehicles. The modern bridge opened in 1930; it was dedicated in 1980 as the
Veterans Memorial Bridge.
125:
The remaining
Conejohela Flats provide habitats for a number of species. The varying depths of inundated islands on the bottom of Lake Clarke support numerous fresh water feeder fish, pan fish, and large predatory
60:
The varied terrain created many nurturing biological habitats, but human passage across the valley and river was extremely difficult. The
Susquehanna is very wide in this area, as it nears its mouth on the
113:
had the largest effect on the river ecosystem. When it first closed its gates on
September 29, 1931, it flooded more than 10 miles of the upper Conejohela Flats, creating the artificial
297:
151:
90:
Three dams were built across the
Conejohela Valley during the first four decades of the 20th century to provide hydroelectric power for southern Pennsylvania (including
302:
117:. Most of the valley was flooded. The few islands that remain in Lake Clarke are a gathering of low, marshy flats about five miles north of Safe Harbor Dam.
292:
91:
198:
57:
wide, flat valley formed; the frequently wide river was a substantial barrier to crossing, both for Native
Americans and for colonists.
307:
248:
78:
287:
66:
240:
156:
36:
in the United States. The valley was flooded primarily during the early 1900s by the construction of the
70:
94:) and to control the annual flooding. It was intended to keep sediment from the flats out of the
219:
74:
25:
161:
110:
45:
146:
137:
ecosystem also support dozens of species of birds; the flats are popular among birders.
95:
62:
281:
178:
171:
103:
41:
166:
99:
37:
29:
114:
263:
250:
127:
130:
species. The Safe Harbor Dam has become a popular area for local fishing.
134:
33:
24:, a large floodplain along the southernmost 30 miles (50 km) of the
65:. This stifled trade across the lower Susquehanna in colonial
152:
77:
was established to cross the river. Later the first
92:
electrical power for Amtrak and SEPTA Regional Rail
102:, was completed in 1910 as McCalls Ferry Dam. The
98:. The first dam across the lower Susquehanna, the
8:
298:Landforms of Lancaster County, Pennsylvania
199:"Conejohela Valley (homepage, directory)"
201:. Conejohela Valley Chamber of Commerce
190:
303:Landforms of York County, Pennsylvania
20:are a group of islands in the flooded
7:
293:Crossings of the Susquehanna River
14:
241:Safe Harbor Water Power Company
220:"Conejohela Flats / FrontPage"
1:
79:Columbia-Wrightsville Bridge
224:conejohelaflats.pbworks.com
324:
133:The low-lying islands and
48:dams from 1910 to 1931.
308:Islands of Pennsylvania
157:Susquehanna River dams
52:Geography and history
260: /
106:followed in 1928.
288:Susquehanna River
264:39.986°N 76.474°W
26:Susquehanna River
22:Conejohela Valley
315:
275:
274:
272:
271:
270:
265:
261:
258:
257:
256:
253:
228:
227:
216:
210:
209:
207:
206:
195:
18:Conejohela Flats
323:
322:
318:
317:
316:
314:
313:
312:
278:
277:
269:39.986; -76.474
268:
266:
262:
259:
254:
251:
249:
247:
246:
237:
232:
231:
218:
217:
213:
204:
202:
197:
196:
192:
187:
162:Safe Harbor Dam
143:
123:
111:Safe Harbor Dam
88:
73:. In 1730, the
54:
12:
11:
5:
321:
319:
311:
310:
305:
300:
295:
290:
280:
279:
244:
243:
236:
235:External links
233:
230:
229:
211:
189:
188:
186:
183:
182:
181:
176:
175:
174:
169:
164:
154:
149:
142:
139:
122:
119:
96:Chesapeake Bay
87:
84:
75:Wright's Ferry
63:Chesapeake Bay
53:
50:
13:
10:
9:
6:
4:
3:
2:
320:
309:
306:
304:
301:
299:
296:
294:
291:
289:
286:
285:
283:
276:
273:
242:
239:
238:
234:
225:
221:
215:
212:
200:
194:
191:
184:
180:
179:Thomas Cresap
177:
173:
172:Conowingo Dam
170:
168:
165:
163:
160:
159:
158:
155:
153:
150:
148:
145:
144:
140:
138:
136:
131:
129:
120:
118:
116:
112:
107:
105:
104:Conowingo Dam
101:
97:
93:
85:
83:
80:
76:
72:
68:
64:
58:
51:
49:
47:
43:
39:
35:
31:
27:
23:
19:
245:
223:
214:
203:. Retrieved
193:
167:Holtwood Dam
147:Cresap's War
132:
124:
108:
100:Holtwood Dam
89:
67:Pennsylvania
59:
55:
30:Pennsylvania
21:
17:
15:
267: /
115:Lake Clarke
46:Safe Harbor
282:Categories
255:76°28′26″W
252:39°59′10″N
205:2010-11-29
185:References
128:game fish
42:Conowingo
141:See also
135:riparian
86:Flooding
71:Maryland
38:Holtwood
34:Maryland
121:Habitat
44:, and
109:The
69:and
32:and
16:The
28:in
284::
222:.
40:,
226:.
208:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.