Vision for a WorldWIDE Fluvial-Sediment Information Network
* U.S. Geological
Survey, 415 National Center,
phone 001 (703) 648.5318
** U.S. Geological
Survey,
phone 001 (520) 670.6821
The nations of the world suffer both from the deleterious effects of some natural and human-altered fluxes of fluvial sediment and a lack of consistent and reliable information on the temporal and spatial occurrence of fluvial sediments. Decades ago, this difficulty was unavoidable due to a lack of understanding of the magnitude and scope of environmental influences exerted by fluvial sediment coupled with a dearth of tools for monitoring and studying the data. Such is no longer the case.
Fluvial sediment has a broad influence on the environment and humanity. Data needs that were once limited primarily to reservoir and channel maintenance now include issues associated with public water supply; contaminated sediment management; productivity of agricultural lands; stream restoration and watershed health; in-stream biotic stability; post-wildfire channel morphology; dam decommissioning, rehabilitation, or removal; and legal requirements for sediment management (Gray and Glysson, 2005).
The adverse effects of poorly managed or unmanaged sediment movement
related to these and other issues are well-known qualitatively, and in some
cases quantitatively. For example, physical, chemical, and biological damages
attributable to fluvial sediment in
Based on the need for more, and more consistent and reliable fluvial-sediment information and on the existence of the ISI and other international and national sediment programs, we envision the need for a Worldwide Fluvial Sediment-Information Network (WoFSIN) with a focus on data acquisition, storage, and dissemination globally. Envisioned components of a WoFSIN, administered largely via the Internet and relying mostly on the benefits derived from existing resources and programs, follow that summary. The goal of the WoFSIN is to maximize the availability and usefulness of the world’s historical and current fluvial-sediment and ancillary data through collaboration with existing programs so as to require few additional resources in the long-term. Thus, the WoFSIN concept was developed recognizing that informed resource management is predicated on the availability of adequate and reliable information.
The WoFSIN is
described in the ensuing sections in stand-alone fashion, followed by a section
that describes the complementary aspects of the WoFSIN
and the International Sediment Initiative. Thus, our first objective is to
describe the fundamental components of a WoFSIN. Our
second objective is to identify overlap or gaps between the WoFSIN and ISI concepts that might
be useful in refining the ISI’s ability to meet its
global mission to develop decision support for sediment management at the
global scale more fully, cost-effectively, and (or) with enhanced quality.
Fluvial-sediment information includes primary numerical information – data – describing selected characteristics of fluvial sediment, such as concentrations, rates of erosion, transport, and deposition, and chemical quality; and other information, such as results of syntheses of the primary data. A maximally useful and responsive WoFSIN would include data-collection and data–mining components along with research and synthesis components.
At least six attributes seem fundamental and essential for the development of a functional WoFSIN. Each is predicated on international consistency and quality assurance in its implementation. The six attributes are:
Synopses of the key characteristics of the attributes and the authors’ necessarily subjective prognosis for their implementation appear in the ensuing sections.
Synopsis: Traditional instruments (fig. 1) and the manually intensive methods for collecting sediment data tend to produce relatively accurate but temporally sparse and costly datasets. These methods also pose safety concerns. Although the historical and contemporary data produced by these techniques tend to be the most accurate sediment data available and are of exceptional scientific and societal value, the unit cost of obtaining these data tends to be high and increasingly costly. Hence, the acquisition of new data has tended to decrease over the last decades. For example, the amount of nationally consistent daily suspended-sediment data produced in 2005 by the U.S. Geological Survey (USGS) was about one third of those collected in 1982 (Gray and Glysson, 2005).
Figure 1. Photographs showing traditional manually deployed instruments for fluvial-sediment data collection used in the United States.: A: US BL-84 bedload sampler, B: US BM-54 bottom-material sampler, C: US DH-48 depth-integrating rigid-bottle suspended-sediment sampler, D: US P-61-A1 point-integrating rigid-bottle suspended-sediment sampler, E(1 and 2): US D-99 depth-integrating bag sampler (side view with sampler close, front view with sampler open, respectively). Federal Interagency Sedimentation Project, 2007.
Use of
these traditional instruments and methods is increasingly being replaced by
less expensive, demonstrably safer, continuously recording in-situ or
laboratory methods for monitoring water clarity and (or) for obtaining
fluvial-sediment data by surrogate technologies (Gray and Glysson,
2005). Turbidity and related bulk-optic measurements are the most common means
for obtaining water-clarity data, and for inferring suspended-sediment
concentrations (Gray and Glysson, 2003). Other
sediment-surrogate techniques, including those based on laser-optic,
digital-optic, hydroacoustic, and
pressure-differential technologies, also are being deployed and (or) tested in
field and laboratory settings for their applicability toward providing
quantifiably reliable information on bed-form and bed-material characteristics,
and on concentrations, size-distributions and transport rates of suspended
sediment and (or) bedload (Gray and others, 2005).
Fig. 2 shows selected instruments that operate on bulk-optic, laser, and
acoustic principles (Gray and Gartner, 2006).
Most of these surrogate technologies (Bogen and others, 2003; Gray and Gartner, 2005) have been
developed commercially (e.g., Gray and others, 2004) and by universities or
other research organizations (e.g.,
Figure 2. Photographs showing selected surrogate instruments for monitoring suspended sediment: A: Submerged nephelometer (left-most instrument; photograph by Mark Uhrich, U.S. Geological Survey) B: LISST-SL suspended-sediment concentration, particle-size, and velocity profiler (Sequoia Scientific, Inc., 2004) C: Depiction of a submerged acoustic backscatter sensor with dual hypothetical conical acoustic beams emanating from the sensor (SonTek, 2007)
Prognosis:
With the exception of continuous turbidity monitoring, none of these
sediment-surrogate technologies has unequivocally emerged from the realm of research
(a protocol for estimating sediment concentrations from turbidity data is being
developed by the USGS). The long-term prospects for surrogate instruments are
to provide reliable information at low,
although cost-savings over traditional techniques will not be realized in the
short term due to intensive data-analysis requirements.
Major progress is anticipated toward operational deployment of some of the other surrogate technologies, particularly active hydroacoustics for suspended-sediment monitoring (Topping and others, 2006) and active and passive hydroacoustics for bedload monitoring (Rennie and others, 2002; Barton and others, 2006) in perhaps the next half decade.
Synopsis: Protocols for fluvial-sediment data collection and analyses by traditional techniques are available internationally and at national and sub-national levels. For example, the International Organization for Standardization (2007) offers protocols for measuring suspended sediment (ISO 4363. 4365, and11329), bed material ((ISO 4364 and 9195), and bedload (ISO TR 9212). USGS protocols for sediment-data collection (Edwards and Glysson, 1999; Nolan and others, 2005; Gray, 2006), laboratory methods (Guy, 1969) and sediment-discharge computations (Porterfield, 1972; Koltun and others, 2006) are well-established.
Consistency in protocols among monitoring
programs, however, is inadequate. For example, the USGS deploys standardized
Federal Interagency Sedimentation Project (2007) (Davis, 2005) isokinetic samplers by the discharge-integrating techniques
described by Edwards and Glysson (1999) and performs
physical analyses of the samples according to methods described by ASTM
International (2000) and Guy (1969). On
Not surprisingly, protocols for sediment-surrogate technologies are largely lacking even though some effort is being directed to this end. For example, the USGS has developed guidelines for estimating sediment concentrations from discrete or time-series turbidity and water-discharge data, along with a means to estimate uncertainty in derived concentration values based on several assumptions.. Regardless, the transition from traditional to surrogate technologies in the field and laboratory requires calibration and verification, which in turn are contingent on the validity and comparability of the traditional technique used.
Prognosis: The world’s various sediment-monitoring equipment and data-collection protocols are unlikely to consolidate into a single standardized set in the coming decade, if ever. Although this does not bode well for an international sediment-information network, it does have the benefit of retaining temporal consistency within monitoring programs. As surrogate technologies find their niche for monitoring programs, protocols developed locally should be compared by an oversight organization, the best characteristics culled from those protocols, and a proposed set of international protocols developed and published for each technology. Part and parcel to this effort would be the inclusion of protocols describing sediment-sampling and analytical methods in the National Environmental Methods Index (2007).
Synopsis: Considerable progress in database development, storage, management, and data-dissemination capabilities has been made in recent decades. The proliferation of electronic spreadsheets and relational databases coupled with relatively inexpensive electronic storage capabilities has greatly enhanced the types and amounts of sediment and ancillary data being stored. The role of the Internet in revolutionizing data sharing would be difficult to overstate. Without the Internet, worldwide sharing of fluvial-sediment data with even a modicum of efficiency and cost-effectiveness is infeasible.
The most robust and useful databases are those that:
(Daniel J. Sullivan, U.S. Geological Survey, written commun. 2007):
National databases that feature all or most of these characteristics
are available. For example, the STORET database (U.S. Environmental Protection
Agency, 2007) and the National Water Information System – Web (NWISWeb; U.S. Geological Survey 2007; Turcios
and others, 2000) contain the bulk of the electronically available, nationally
consistent fluvial-sediment and ancillary data in the
Several international databases that include various types of fluvial-sediment data exist. For example, the GEMStat database (Barker, 2006; Global Environment Monitoring System, 2007) contains information related to sedimentation in impoundments behind small dams. SedWeb (2007) provides information on contaminated sediment management and research. However, no international database has been identified that meets both the aforementioned “robust and useful” criterion and that also contains diverse data types (time-series, at-a-point, and spatial data) describing the requisite fluvial sediment for solving complex fluvial-sediment problems. Additionally, the general inconsistency in worldwide data-collection and data–analysis protocols may result in uncertainty with respect to the comparability of data retrieved from multiple national databases.
In summary, among the plethora of sediment and other water-quality databases worldwide, at least several have characteristics and capabilities that would be desirable in a truly worldwide sediment database.
Prognosis: There are at least two approaches to address WoFSIN database requirements.
1. An organization with expertise in sediment- and water-quality database development and management should evaluate the availability and capabilities of existing water-quality databases based on criteria from the world sediment-research community and make a recommendation on how to obtain and use databases for worldwide sediment data availability. This would result in the most consistent databases containing the most comparable data. However, it also would require substantial resources, both in database development and maintenance.
2. Compile information on all available and useful databases of collaborating nations or organizations; identify and define metadata requirements for a set of properties of interest for inclusion in a WoFSIN; and develop an Internet search engine to extract data and, where available, metadata and related collection and analysis protocols from the databases based on logical queries. This approach would result in accrual of data without compelling users to populate or maintain a database. However, this approach may fail to provide adequate information on protocols to quantify data quality and enable valid comparisons of similar data types.
Synopsis: Acquisition of quality-assured, consistent fluvial-sediment data; their storage; and their dissemination is but a means to an end. Analyses of these data are required for use in derivation of useful sediment-management techniques. A maximally useful WoFSIN is predicated on a research component with at least the following three capabilities:
1. Research on Instrument and Methods Development: This represents a re-investment in data-collection activities by improving upon, or developing, new instruments and/or protocols. The USGS’s informal Sediment Monitoring Instrument and Analysis Research Program (Gray and Glysson, 2005) includes an instrument- and methods-development component.
2. Data Syntheses: A mature WoFSIN dataset – presumably unprecedented in size, and perhaps breadth – will form the basis for fundamental and applied research on sedimentary processes. A WoFSIN would be best served by ceding leadership in data syntheses to researchers in universities and other organizations based on the concept, “build it and they will come”, which has been demonstrated many times over through usage of USGS sediment data by a diverse community of researchers worldwide.
3. Characterizations of Uncertainty: One substantial impediment to the usefulness and applicability of fluvial-sediment data is the general lack of uncertainty estimates associated with these data. Relative uncertainty estimates would greatly aid researchers and managers to resolve the margin-of-error component when considering sediment-management options.
Prognosis: The world is rich in analytical resources, particularly through universities and other public and private research institutions. It is anticipated that most research based on WoFSIN resources will take place in a distributed manner at zero or inconsequential direct cost to the WoFSIN.
Synopsis: The resources needed to collect, analyze, quality-assure, store, and disseminate fluvial-sediment and ancillary data on a worldwide basis are likely to exceed the resources directly available to the WoFSIN, by perhaps orders of magnitude. Hence, the WoFSIN will need to take advantage of resources – data and protocols – from selected existing international, national, and sub-national programs that focus on fluvial-sediment data or collect these as ancillary data.
Prognosis: A
number of international programs, including the International Sedimentation
Initiative (2007) of the International Research and Training Centre for Erosion
and Sedimentation (2007), the Vigil Network (2007), the Bedload
Research International Cooperative (2004) and the Global Environment Monitoring
System (Barker, 2006; GEMStats, 2007) will be sought
as collaborators. National and sub-national programs, such as the USGS’s National Water Information System-Web (U.S. Geological Survey, 2007) are numerous,
if unevenly distributed by nation, and have inconsistent protocols for the
collection, analysis, and storage of data.
Synopsis: A WoFSIN will require planning, implementation, and maintenance such that only can be provided – barring a large infusion of funds, which is not anticipated – by an existing organization with a mandate in fluvial-sediment information acquisition and dissemination, and an international scope.
Prognosis:
As stated previously, the WoFSIN concept includes a
number of attributes that are complementary and, not surprisingly, redundant
with the ISI. The authors suggest that the non-redundant, cost-effective, and
most useful attributes of the WoFSIN be absorbed into
the ISI, if feasible. If not, there are at least two international programs,
both UNESCO-supported, that possess particularly
strong credentials to lead a WoFSIN: The
International Research and Training Centre for Erosion and Sedimentation
(IRTCES; 2007), which has implementation responsibility for the ISI; and the
World Association for Sedimentation and Erosion Research (WASER; 2007). The
authors suggest that the ISI Steering Committee, IRTCES, and WASER consider the
concepts proposed herein and decide which, if any, are sufficiently tractable
and worth implementing. The USGS is able and willing to provide advice toward
framing and implementing any or all of the six WoFSIN
attributes, as might be other selected organizations, such as the
As noted previously, the WoFSIN is considered to be complementary to the activities and projects of the International Sedimentation Initiative (2007). Following are the major activities and projects of the ISI with succinct comparisons germane to each WoFSIN attribute.
ISI 1—Global Evaluation of
Sediment Transport (GEST) Project: GEST assesses
the sediment budgets in river basins and estimates the total sediment load
entering the ocean to create a global repository for data, information, and
documentation on soil erosion and sediment transport.
Relevance of the WoFSIN: The much-needed GEST Project is beyond the scope of the WoFSIN, but might benefit from the global information made available through a WoFSIN. The WoFSIN concept favors accessing existing distributed databases that are maintained externally as opposed to centrally maintained database, which can entail considerable quality-assurance, maintenance, and cost issues.
ISI 2—Initiation of case studies for river basins as demonstration projects: Case studies will offer examples of monitoring and data-processing techniques, procedures and methodologies for analysis of environmental, economic and social impacts, and evaluation of management practices.
Relevance of the WoFSIN: Although the WoFSIN concept does not include case studies – mainly for financial reasons – it is fully compatible with, and potentially beneficial to, the development of consistent, credible case studies.
ISI 3—Setting up a global erosion and sediment
information system: The sediment information system would be comprised of at least three
main components:
a. Database to be generated from GEST and case studies.
b. Global Sediment Portal with links to other data sources.
c. Documentation on information development, showing how to extract information out of scarce, scattered and unreliable data, and instructions on how to set up sediment databases for river basins in different parts of the world.
Relevance of the WoFSIN: This WoFSIN concept has the most relevance to ISI with respect to components (a) and (c). As noted under the GEST discussion (a) above, the WoFSIN distributed-database concept with search engines may be a more tractable and cost-effective approach to information acquisition and serving than a central database. The WoFSIN “data collection and analysis protocols” attribute should be part-and-parcel with the ISI goal on database set-up, and is consistent with the WoFSIN distributed-database concept.
ISI 4—Review of sediment related research: Information on ongoing research is an important contribution to the operation of the databases and information systems; however, the inadequacy of knowledge about various aspects of erosion and sediment phenomena hinders progress in addressing key sedimentation problems.
Relevance of the WoFSIN: This ISI concept is related to the WoFSIN “Basic and Applied Research” attribute. The latter places most of the burden for this endeavor on the distributed but extensive fluvial-sediment research community. The authors believe that existing funded researchers will direct local resources, with little if any need for additional funds, toward syntheses of the data that are made available through the WoFSIN. This may be particularly valuable for syntheses of data from the less-developed nations of the world that might not have the resources to perform such syntheses.
ISI 5—Education and capacity building for sustainable sediment management: Identifying multiple modes of education to satisfy regional requirements and interests in different socio-economic and eco-hydrological settings is a medium-term priority.
Relevance of the WoFSIN: Although there is no direct WoFSIN parallel to this ISI concept, the WoFSIN concept represents a critical link in the “obtain-and-apply-knowledge” chain.
ISI 6—Networking: Open to collaboration with all interested institutions and international, national, or regional associations, ISI aims to establish close working contacts with their projects, programmes, and networks, such as SedNet, GEOSS, Non-Government Organizations, and other entities.
Relevance of the WoFSIN: The WoFFSIN is perhaps the ultimate concept in networking – accessing and serving information from discrete databases worldwide.
The nations of the world would benefit considerably from the formation of a World Fluvial Sediment Information Network, considering that river-process information is largely transferable among river basins, nations, and continents. A WoFSIN is proposed that utilizes existing international, national, and sub-national resources and programs; appropriate databases, instruments, and protocols; and the Internet, without the need for comparatively substantial new resources. Progress occurring in a largely ad hoc manner worldwide in each of these WoFSIN attributes ranges from moderate to substantial. The key point, however, is that much, and perhaps most of the requisite effort on these attributes is on-going and will not require “starting from scratch” by the WoFSIN.
Although the WoFSIN was conceptualized to be independent of other programs, it is fully recognized that its attributes overlap with those of the ISI (2007b). If the useful, non-redundant attributes of the WoFSIN cannot be absorbed into the ISI, the authors suggest that the IRTCES, or the WASER, consider embracing those WoFSIN attributes that are not redundant with the ISI. Regardless, the U.S. Geological Survey is willing and able to provide advice toward the framing and implementation of any or all of the six WoFSIN attributes.
ASTM International, 2000. Standard test methods
for determining sediment concentration in water samples: Designation D 3977-97,
pp. 395-400.
Barker Sabrina, 2006. Sediment data, GEMSTAT and open web services: Abstracts of the International
Sedimentation Initiative Conference,
Barton J.S., Slingerland Rudy, Gabrielson T.B., and Pittman Smokey, 2006. Passive
acoustic monitoring of coarse bedload on the Trinity
River: Proceedings of the 8th Federal Interagency Sedimentation
Conference,
Bogen J., Fergus
T., and Walling D.E., 2003. Erosion and Sediment Transport Measurement in
Rivers – Technological and Methodological Advances: International Association
of Hydrologic Sciences, Publication 283, p. 238.
Bogen Jim and Møen Knut, 2003. Bed load
measurements with a new passive acoustic sensor in Bogen,
J, Fergus, T., and Walling, D.E. Erosion and Sediment Transport Measurement in
Rivers – Technological and Methodological Advances: International Association
of Hydrologic Sciences, Publication 283, pp. 181-192.
Consortium of Universities for the Advancement of Hydrologic Sciences,
2007. Home page (http://www.cuahsi.org/).
Edwards T.E., and Glysson
G.D., 1999. Field methods for measurement of fluvial sediment:
U.S. Geological Survey Techniques of Water-Resources Investigations Book 3,
Chapter C2, 89 p. (http://water.usgs.gov/osw/techniques/Edwards-TWRI.pdf).
Elliott J.G., and Parker R.S., 1999.
Reconfigured-channel monitoring and assessment program: U.S. Geological Survey
Water-Resources Investigations Report 99-4111, 6 p.
(http://pubs.usgs.gov/wri/wri994111/).
Federal Interagency Sedimentation Project, 1940. Field
practice and equipment used in sampling suspended sediment: Report No. 1, 175
p. (http://fisp.wes.army.mil/Report%201.pdf).
Federal Interagency Sedimentation Project, 2007, Home page:
(http://fisp.wes.army.mil/).
Gartner J.W. and Gray J.R., 2005. Summary of
suspended-sediment technologies considered at the interagency workshop on
turbidity and other sediment surrogates, in, Proceedings of the Federal
Interagency Sediment Monitoring Instrument and Analysis Workshop, September
9-11, 2003, Flagstaff, Arizona, J.R. Gray, ed.: U.S. Geological Survey Circular
1276, 9 p. (http://water.usgs.gov/osw/techniques/sediment/sedsurrogate2003workshop/gartner_gray.pdf).
Global Water Monitoring System, 2007. Global
water quality data and statistics: Home page (http://www.gemstat.org/).
Gray J.R., 2006. Measurement of
suspended-sediment transport: Dekker Encyclopedia of Water Science. DOI 10.1081/E-EWS-120042046,
5 p. (http://www.dekker.com/sdek/section?content=
a713627207&scope=doc&fmt=.html).
Gray J.R., Agrawal Y.C., and
Pottsmith H.C., 2004. The LISST-SL
streamlined isokinetic suspended-sediment profiler,
in, Proceedings of the 9th International Symposium on River Sedimentation,
Cheng Liu, ed.:
Gray J.R., and
Gartner J.W, 2006. Overview of selected surrogate technologies for continuous
suspended-sediment monitoring, in,
Proceedings, 8th Federal Interagency Sedimentation Conference, April
2-6, 2006, Reno, Nevada, (ISBN 0-9779007-1-1), 8 p. (http://water.usgs.gov/pubs/
misc_reports/FISC_1947-2006/).
Gray J.R, and Glysson G.D.,
2003. Proceedings of the Federal Interagency Sedimentation Workshop on
Turbidity and Other Sediment Surrogates, April 30-May 2, 2002, Reno, Nevada:
U.S. Geological Circular 1250, 56 p.; appendix 2 contains 29 extended abstracts
which are available only online at: http://water.usgs.gov/osw/techniques/TSS/listofabstracts.htm.
Gray J.R., and Glysson G.D.,
2005. Attributes for a sediment monitoring instrument and analysis research
program, in, Proceedings of the Federal Interagency Sediment Monitoring Instrument
and Analysis Workshop, September 9-11, 2003,
Gray J.R., and Laronne, J.B., 2004.
Coordination of International Bedload Research, in,
Proceedings of the 9th International Symposium on River
Sedimentation, Cheng Liu, ed.: Yichang, China,
October 18-21, 2004, Vol. IV, Tsinghua University
Press, pp. 2501-2506
(http://water.usgs.gov/osw/techniques/sediment/sedsurrogate2003workshop/bric_3_19_2004.pd).
Gray J.R., Melis T.S, Patiño Eduardo, Gooding D.J., Topping D.J., Larsen
M.C., and Rasmussen P.P.,
Global Environment Monitoring System, 2007. Home page (http://www.gemstat.org/).
Guy H.P., 1969. Laboratory theory and methods for sediment analysis:
U.S. Geological Survey Techniques of Water-Resources Investigations Book 5, C1,
58 p. (http://water.usgs.gov/ osw/techniques/Edwards-TWRI.pdf).
International Organization for Standardization, 2007. Home page (http://www.iso.org/iso/en/ ISOOnline.frontpage).
International Research and Training Centre for Erosion
and Sedimentation, 2007. Home page
(http://www.irtces.org/).
International Hydrological Programme, 2007, Home page
(http://typo38.unesco.org/
index.php?id=240).
International Sedimentation Initiative, 2007a. Home page (http://www.irtces.org/isi/).
International Sedimentation Initiative, 2007b. Key issues
addressed by the steering committee, and main activities and projects
(http://www.irtces.org/isi/main-activities.asp).
Koltun G. F. Eberle Michael, Gray J. R., and Glysson G. D, 2006. User's manual for the
Graphical Constituent Loading Analysis System. (GCLAS): U.S Geological Survey
Techniques and Methods Report 4, C1, 51 p.
(http://pubs.er.usgs.gov/usgspubs/tm/tm4C1).
Laronne J.B., and Gray J.R., 2005. Formation of a Bedload Research International
Cooperative, in, Proceedings of the
Federal Interagency Sediment Monitoring
Instrument and Analysis Workshop, September 9-11, 2003, Flagstaff, Arizona,
J.R. Gray, ed.: U.S. Geological Survey Circular 1276, 9 p. (http://water.usgs.gov/osw/techniques/sediment/sedsurrogate2003workshop/
bric_3_19_2004.pdf).
National Environmental Methods Index, 2007. Home page (http://www.nemi.gov/).
Nolan K.M., Gray J.R. and Glysson
G.D., 2005. Introduction to suspended-sediment sampling: U.S.
Geological Survey Scientific Investigations Report 2005-5077, available on
CD-ROM and at: http://pubs.er.usgs.gov/pubs/sir/sir20055077.
Osterkamp W. R., Heilman P., and Lane L. J., 1998. Economic
considerations of a continental sediment-monitoring program: International
Journal of Sediment Research, v. 13, no. 4, p.
12-24 (http://water.usgs.gov/osw/techniques/Osterkamp.html).
Osterkamp W. R., Heilman Philip, and Gray J. R., 2004. An
invitation to participate in a North American sediment-monitoring network: Eos,
Transactions, American Geophysical Union, v. 85, no. 40, p. 386, 388.
Pimentel David, Harvey C., Resosudarmao P.,
Sinclair K., Kurz D., McNair M., Crist
S., Shpritz L., Fitton L., Saffouri R., and Blair R., 1995. Environmental and economic
costs of soil erosion and conservation benefits: Science, v. 267, p. 1117-1123.
Porterfield, George, 1972. Computation of fluvial-sediment discharge:
U.S. Geological Survey Techniques of Water-Resources Investigations Book 3, C3,
66 p. (http://pubs.er.usgs.gov/ usgspubs/twri/twri03C3).
Rennie, C.D., Millar, R.G., and Church, M.A. (2002). Measurement of bedload velocity using an
acoustic Doppler current profiler. J. Hydraulic Engineering,
128(5):473-483.
SedWeb, 2007, Home page (http://www.sediments.org/).
Sequoia Scientific, Inc. 2007. Home page
(http://www.sequoiasci.com/default.aspx?Section
Name=home).
SonTek, 2007. Home page (http://www.sontek.com/).
Stallard R.F., Mixon D., Kinner D.A., and Worstell B.,
2001. RESIS-II: Making the reservoir survey system
complete and user friendly: Proceedings of the Seventh Federal Interagency
Sedimentation Conference,
Topping D. J, Wright S.A., Melis
T.S, and Rubin D.M., 2006. High-resolution monitoring of suspended-sediment
concentration and grain size in the Colorado River using laser-diffraction instruments
and a three-frequency acoustic system: Proceedings of the 8th
Federal Interagency Sedimentation Conference, Reno, Nevada, April 2-6. 8 p. (http://pubs.usgs.gov/misc_reports/
FISC_1947-2006/pdf/1st-7thFISCs-CD/8thFISC/Session%206C-3_Topping.pdf).
Turcios L.M., Gray J.R., and Ledford A.L., 2000. Summary
of U.S. Geological Survey on-line instantaneous fluvial sediment and ancillary
data (http://water.usgs.gov/osw/sediment/).
Vigil Network, 2007. Home
page (http://wwwpaztcn.wr.usgs.gov/vigil/).
World Association for Sedimentation and Erosion Research, 2007. Home page (http://www.waser.cn/).