The Paleocene–Eocene-aged Sele Formation is developed across the basinal region of the Central North Sea. The section comprises a number of deep-marine fan systems that expanded and contracted across the basin floor in response to relative sea-level changes on the basin margin and fluctuating sediment yield off the Scottish landmass modulated by climate and hinterland uplift. Persistent sediment entry points to the basin resulted in the development of discrete axial and transverse fan fairways with a geometry dictated by an irregular bathymetry sculpted by differential compaction across Mesozoic faults, halokinesis and antecedent fan systems. A high-resolution biostratigraphic framework has allowed the evolution of fan-dispersal systems in response to these effects to be tracked across the basin within four genetic sequences. The proximal parts of the fans comprised channel complexes of low sinuosity, high lateral offset, and low aggradation. The development of these systems in a bathymetrically confined corridor of the Central Graben (c. 65 km wide), combined with high sediment supply, resulted in the eventual burial of any underlying relief. The behaviour of sand-rich reservoirs in this region is dominated by the permeability contrast between high-quality channel fairways and more heterolithic overbank regions, with the potential for early water breakthrough and aquifer coning in the channel fairways, and unswept volumes in overbank locations. Compartmentalization of compensationally stacked channel bodies occurs locally, with stratigraphic trapping caused by lateral channel pinch-outs, channel-base debrites, mud-rich drapes and abandonment fines. Towards the southern part of Quadrant 22, approximately 150 km down-palaeoflow, the systems became less confined and in this region are dominated by channel–lobe complexes, which continued to interact with an irregular bathymetry controlled by antecedent fans, mass-transport complexes and halokinesis in the form of rising salt diapirs. Reservoirs in this region are inherently stratigraphically compartmentalized by their heterolithic lithology and compensational stacking of lobes, and further complicated by structuration and instability induced by the diapiric or basement structures needed to generate a trapping structure in these settings.

There is clear evidence that the Minnesota River is the major sediment source for Lake Pepin and that the Le Sueur River is a major source to the Minnesota River. Turbidity levels are high enough to require management actions. We take advantage of the well-constrained Holocene history of the Le Sueur basin and use a combination of remote sensing, field, and stream gauge observations to constrain the contributions of different sediment sources to the Le Sueur River. Understanding the type, location, and magnitude of sediment sources is essential for unraveling the Holocene development of the basin as well as for guiding management decisions about investments to reduce sediment loads. Rapid base-level fall at the outlet of the Le Sueur River 11,500 yr B.P. triggered up to 70 m of channel incision at the mouth. Slope-area analyses of river longitudinal profiles show that knickpoints have migrated 30–35 km upstream on all three major branches of the river, eroding 1.2–2.6 × 109 Mg of sediment from the lower valleys in the process. The knick zones separate the basin into an upper watershed, receiving sediment primarily from uplands and streambanks, and a lower, incised zone, which receives additional sediment from high bluffs and ravines. Stream gauges installed above and below knick zones show dramatic increases in sediment loading above that expected from increases in drainage area, indicating substantial inputs from bluffs and ravines.

The Western Escarpment of the Andes at 18.30°S (Arica area, northern Chile) is a classical example for a transient state in landscape evolution. This part of the Andes is characterized by the presence of >10,000 km2 plains that formed between the Miocene and the present, and >1500 m deeply incised valleys. Although processes in these valleys scale the rates of landscape evolution, determinations of ages of incision, and more importantly, interpretations of possible controls on valley formation have been controversial. This paper uses morphometric data and observations, stratigraphic information, and estimates of sediment yields for the time interval between ca. 7.5 Ma and present to illustrate that the formation of these valleys was driven by two probably unrelated components. The first component is a phase of base-level lowering with magnitudes of∼300–500 m in the Coastal Cordillera. This period of base-level change in the Arica area, that started at ca. 7.5 Ma according to stratigraphic data, caused the trunk streams to dissect headward into the plains. The headward erosion interpretation is based on the presence of well-defined knickzones in stream profiles and the decrease in valley widths from the coast toward these knickzones. The second component is a change in paleoclimate. This interpretation is based on (1) the increase in the size of the largest alluvial boulders (from dm to m scale) with distal sources during the last 7.5 m.y., and (2) the calculated increase in minimum fluvial incision rates of ∼0.2 mm/yr between ca. 7.5 Ma and 3 Ma to ∼0.3 mm/yr subsequently. These trends suggest an increase in effective water discharge for systems sourced in the Western Cordillera (distal source). During the same time, however, valleys with headwaters in the coastal region (local source) lack any evidence of fluvial incision. This implies that the Coastal Cordillera became hyperarid sometime after 7.5 Ma. Furthermore, between 7.5 Ma and present, the sediment yields have been consistently higher in the catchments with distal sources (∼15 m/m.y.) than in the headwaters of rivers with local sources (<7 m/m.y.). The positive correlation between sediment yields and the altitude of the headwaters (distal versus local sources) seems to reflect the effect of orographic precipitation on surface erosion. It appears that base-level change in the coastal region, in combination with an increase in the orographic effect of precipitation, has controlled the topographic evolution of the northern Chilean Andes.

Human activities impact an estimated 98% of rivers in the United States. This chapter summarizes impacts associated with pioneer societies, commercial activities, and public works. In pioneer societies, individuals or small groups undertake activities such as timber harvest, agriculture, or navigation improvements. Nineteenth-century placer mining of gold along rivers of California's Sierra Nevada is used as a case study. Commercial activities are conducted by groups of people seeking profit through industry, commerce, or agriculture. Commercial activities impacted rivers much more extensively than most activities of pioneer societies. Impacts to water quality, and particularly the U.S. Geological Survey National Water Quality Assessment (NAWQA) program, provide a case study. Results from the 1991–1995 NAWQA program indicate that approximately half the sites sampled in urban areas have surface-water contamination exceeding levels at which adverse biological effects can occur in aquatic biota. Public works such as dam and levee construction undertaken by local and federal governmental agencies caused massive alteration of river systems. Channelization is used as a case study of the impacts of public works on rivers; more than 56,000 km of waterways were channelized by the Corps of Engineers and the Soil Conservation Service after 1940.The net effect of human activities in the United States has been to disconnect rivers from adjacent hillslopes, floodplains, and valley bottoms, underlying hyporheic and groundwater zones, and from headwaters and downstream processes. Because a connected river is a functioning ecosystem, rather than simply a canal for moving water and sediment, disconnection simplifies and impoverishes the ecosystem. This has resulted in widespread loss of biological diversity in rivers of the United States.

Climate is the first-order control on fluctuations of glacial tidewater termini. However, factors affecting relative water depth such as eustasy, isostasy, and sediment yield are important second-order controls on termini fluctuations. Deposition of grounding-line systems, which include ice-contact deltas, morainal banks, and grounding-line fans, can change relative water depth and consequently alter the stability of tidewater termini independent of climate. Therefore, the rate at which sediment accumulates in these grounding-line systems can control the rate of terminus movement. Modern temperate glaciers at Glacier Bay, Alaska, on average produce about 106 m3/yr of sediment, most of which accumulates at grounding lines. Sediment volume decreases logarithmically downfjord from a grounding line. In Glacier Bay, readvance rates that average about 10 m/yr are one to two orders of magnitude slower than retreat rates. Rates of glacial advance may be a function of sediment yield (determined by drainage area and rates of glacial erosion, transportation and debris release), total sediment volume of grounding-line systems (determined by fjord width, fjord depth less the maximum water depth for terminus stability, and angle of repose of sediment making the system), and sediment dispersal patterns (determined by process of debris release and dispersion, type of sediment, and marine currents). Consequently, average rates of advance are slower than retreat rates because of the time required for sediment to accumulate as a bathymetric high at a grounding line, which effectively decreases relative water depth and increases terminus stability. Retreat rates are faster because they occur during terminus instability in deep water and cannot be altered by sediment accumulation rates until quasi-stability of the terminus is caused by other means, such as bedrock pinning-points or a decrease in ablation area. As marine-ending glaciers expand, total sediment delivered to a grounding line increases; as they retreat, sediment volume decreases because of the change in size of the drainage basin. Grounding lines are the major depocenters receiving this sediment, and resulting lithofacies packages and geometries are primarily controlled by grounding-line movement over a glacial advance-retreat cycle. During glacial minima, fjords trap sediment while the continental shelf and slope are starved. During glacial advances and retreats, fjords are eroded while the continental shelf receives sediment and the slope may remain starved. At glacial maxima, fjords and commonly the shelf are eroded, and the continental slope receives sediment. Because grounding-line advance and retreat may or may not coincide with eustatic sea-level changes, the sedimentary record may vary depending on environmental settings and the magnitude of glacial cycles.