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H.N. Flippo

Publications and source records attributed to H.N. Flippo.

10 recordsLinked to original sources
USGS1995

Deposition and simulation of sediment transport in the Lower Susquehanna River reservoir system

The Susquehanna River drains 27,510 square miles in New York, Pennsylvania, and Maryland and is the largest tributary to the Chesapeake Bay. Three large hydroelectric dams are located on the river, Safe Harbor (Lake Clarke) and Holtwood (Lake Aldred) in southern Pennsylvania, and Conowingo (Conowingo Reservoir) in northern Maryland. About 259 million tons of sediment have been deposited in the three reservoirs. Lake Clarke contains about 90.7 million tons of sediment, Lake Aldred contains about 13.6 million tons, and Conowingo Reservoir contains about 155 million tons. An estimated 64.8 million tons of sand, 19.7 million tons of coal, 112 million tons of silt, and 63.3 million tons of clay are deposited in the three reservoirs. Deposition in the reservoirs is variable and ranges from 0 to 30 feet. Chemical analyses of sediment core samples indicate that the three reservoirs combined contain about 814,000 tons of organic nitrogen, 98,900 tons of ammonia as nitrogen, 226,000 tons of phosphorus, 5,610,000 1tons of iron, 2,250,000 tons of aluminum, and about 409,000 tons of manganese. Historical data indicate that Lake Clarke and Lake Aldred have reached equilibrium, and that they no longer store sediment. A comparison of cross-sectional data from Lake Clarke and Lake Aldred with data from Conowingo Reservoir indicates that Conowingo Reservoir will reach equilibrium within the next 20 to 30 years. As the Conowingo Reservoir fills with sediment and approaches equilibrium, the amount of sediment transported to the Chesapeake Bay will increase. The most notable increases will take place when very high flows scour the deposited sediment. Sediment transport through the reservoir system was simulated with the U.S. Army Corps of Engineers' HEC-6 computer model. The model was calibrated with monthly sediment loads for calendar year 1987. Calibration runs with options set for maximum trap efficiency and a "natural" particle-size distribution resulted in an overall computed trap efficiency of 34 percent for 1987, much less than the measured efficiency of 71 percent.

Water-Resources Investigations Report↗
USGS1994

Calibration of a streamflow-routing model for the Delaware River and its principal tributaries in New York, New Jersey, and Pennsylvania

The flow-routing module of the Hydrologic Simulation Program-Fortran watershed model was calibrated for 31 reaches on the Delaware River and 5 of it principal tributaries. These calibrations primarily involved the development of discharge-storage volume relations for the defined reaches. Daily discharge records for stream-gaging stations located at the upstream ends of the study reaches on the respective streams provided the primary hydrographic inputs for the routing models. Streamflow records for gaging stations at upstream locations and on other tributaries were used to estimate all other inflows for the 5-year calibration period, 1979-83. Root mean square errors of streamflows that were simulated for the downstream ends of gaged reaches ranged from 0.4 to 9.4 percent for the Delaware River, Lehigh River, Schuylkill River, and Brandywine Creek. Errors of 13 and 30 percent resulted from the streamflow simulations for the Lackawaxen and Neversink Rivers, respectively. Verification simulations for a 3-month period of extreme low flows on the Delaware River in 1966 resulted in overestimation of discharges for the Trenton, NJ, gaging station by approximately 50 percent on many days. Observed (recorded) streamflows at the Trenton gaging station during this time were exceptionally low, owing to comparatively large diversions of flow for public supplies, and into the Delaware and Raritan Canal. A flow-verification simulation for 3 months of the summer and fall of 1985, during which time minimum flows in the basin were comparable to those of 1966, resulted in a root mean square error of 3.3 percent for the Trenton gaging station. There was no diversion to the Delaware and Raritan Canal at the time. Simulated flows closely matched observed flows for upstream gaging stations on the Delaware River as well, thereby confirming the routing calibration for this stream. Information contained in this report can be used, with little modification, to develop routing modules for full-scale applications of the Hydrologic Simulation Program FORTRAN model to the watersheds of the studied streams.

Water-Resources Investigations Report↗
USGS1988

Low-flow routing in the Lehigh and Delaware Rivers, Pennsylvania

Flow-routing studies were made to evaluate the response of the Lehigh and Delaware Rivers to low-flow augmentative releases from two reservoirs --Francis E. Walter Reservoir and Beltzville Lake--in the Lehigh River basin. Digital routing models that use diffusion-analogy methods to convolute flows with system-response functions were developed to simulate daily flows at selected sites. Model errors, for five sites and for periods of 1 year or more, were mostly between 3 and 12 percent in terms of absolute errors in daily flows and were mostly within 4 percent for flow volumes. The developed models were satisfactory for predicting hydrographic response at eight sites in the reach from White Haven, Pennsylvania to Trenton, New Jersey. However, abrupt changes in the flow rate of the Lehigh River at the Bethlehem and the Glendon gaging stations could not be adequately replicated with the model. The model tends to underestimate peaks by as much as 30 percent and to overestimate some low flows of short duration by as much as 20 percent. This occurs primarily because inflows from ungaged areas could not be reliably modeled throughout their ranges by use of flow records for gaged streams. The model will underestimate long-duration low flows at the Glendon site for periods when underflows at the gaging stations on Little Lehigh and Monocacy Creeks are significant. The models were used to route hypothetical releases from Francis E. Walter Reservoir during a low-flow period. The model for the Lehigh River indicated that an added release of 50 ft3/s (cubic feet per second) over a 64-day period during the severe drought in the summer of 1965 would have increased minimum flows for this period at Bethlehem and Glendon by approximately the same amount. A hypothetical release of 200 ft3/s for the period July 20-22, 1965, which is about eight times the actual release in this period, would have been attenuated by about 25 percent when it reached the Bethlehem gage. The synthesized hydrograph for the Bethlehem gage showed such a release would have passed their by July 27. Unresolvable timing errors in the models created an unrealistic hydrographic response for this release at the Trenton gage; but, such a release probably would have passed Trenton by July 29. In order to time the movement of a release wave more accurately than could be done with the developed model, travel times for the wave of an augmentative low-flow release were obtained by field observations and comparisons of gage-height records. The observed leading edge of an abrupt release of 153 ft3/s from Francis E. Walter Reservoir, which ended a 2-day release at a rate of 48 ft3/s, arrived at the gage below the reservoir in 0.5 hour, at White Haven in 3.7 hours, at the mouth of Pohopoco Creek in about 23.1 hours, at Walnutport in 27 hours, at Bethlehem in 39 hours, and at Glendon in 42 hours. This release could not be detected in the record for the Trenton gage. Travel time for an augmentative release in the Lehigh River is dependent upon the pre-release discharge, the relative magnitude of the release, and antecedent rainfall. Relationships are provided for estimating the time of arrival at Walnutport, Bethlehem, and Glendon of the leading edge of waves generated by augmentative releases of 75 to 600 ft3/s. Stage observations on Pohopoco Creek indicated a 2.1-hour travel time between Beltzville Lake and the Lehigh River for the elading edge of a wave produced by a typical augmentative release from this reservoir.

Water-Resources Investigations Report↗
USGS1985

Cost effectiveness of the stream-gaging program in Pennsylvania

This report documents a cost-effectiveness study of the stream-gaging program in Pennsylvania. Data uses and funding were identified for 223 continuous-record stream gages operated in 1983; four are planned for discontinuance at the close of water-year 1985; two are suggested for conversion, at the beginning of the 1985 water year, for the collection of only continuous stage records. Two of 11 special-purpose short-term gages are recommended for continuation when the supporting project ends; eight of these gages are to be discontinued and the other will be converted to a partial-record type. Current operation costs for the 212 stations recommended for continued operation is $1,199,000 per year in 1983. The average standard error of estimation for instantaneous streamflow is 15.2%. An overall average standard error of 9.8% could be attained on a budget of $1,271,000, which is 6% greater than the 1983 budget, by adopted cost-effective stream-gaging operations. (USGS)

Water-Resources Investigations Report↗
USGS1972

Map showing flood of June 1972 resulting from tropical storm Agnes, Susquehanna River at Kingston, Pennsylvania

In June 1972, tropical storm Agnes caused severe flooding within a broad area extending from North Carolina to Southern New York. Flood elevations along the Susquehanna River were the highest ever recorded. In the Wilkes-Barre area, flood elevations exceeded those of 1865 and 1936 by about eight feet. Maximum discharges were about 40 percent greater than those of a 50-year flood. Property damages from flooding in the Wyoming Valley, in which Wilkes-Barre lies, far exceeded those in any are of similar size affected by the storm. The extent of the flooding on the map was delineated by the U.S. Geological Survey from field surveys made soon after the flood. Sections of levees and railroad grades that were not overtopped are not delineated.

Pennsylvania↗
USGS1972

Map showing flood of June 1972 resulting from tropical storm Agnes, Susquehanna River at Wilkes-Barre and Plymouth, Pennsylvania

In June 1972, tropical storm Agnes caused severe flooding within a broad area extending from North Carolina to Southern New York. Flood elevations along the Susquehanna River were the highest ever recorded. In the Wilkes-Barre area, flood elevations exceeded those of 1865 and 1936 by about eight feet. Maximum discharges were about 40 percent greater than those of a 50-year flood. Property damages from flooding in the Wyoming Valley, in which Wilkes-Barre lies, far exceeded those in any are of similar size affected by the storm. The extent of the flooding on the map was delineated by the U.S. Geological Survey from field surveys made soon after the flood. Sections of levees and railroad grades that were not overtopped are not delineated.

Pennsylvania↗
USGS1972

Map showing flood of June 1972 resulting from tropical storm Agnes, Susquehanna River in the vicinity of Wilkes-Barre and Pittston, Pennsylvania

In June 1972, tropical storm Agnes caused severe flooding within a broad area extending from North Carolina to Southern New York. Flood elevations along the Susquehanna River were the highest ever recorded. In the Wilkes-Barre area, flood elevations exceeded those of 1865 and 1936 by about eight feet. Maximum discharges were about 40 percent greater than those of a 50-year flood. Property damages from flooding in the Wyoming Valley, in which Wilkes-Barre lies, far exceeded those in any are of similar size affected by the storm. The extent of the flooding on the map was delineated by the U.S. Geological Survey from field surveys made soon after the flood. Sections of levees and railroad grades that were not overtopped are not delineated.

Pennsylvania↗