40 research outputs found
Evaluation of Hand-Dug Wells in Rural Haiti
Water resources, especially safe, potable water, are limited for many Haitians. In areas where shallow groundwater is available, many household water needs such as laundry, bathing, and cooking are supplied by handâdug wells. In order to better understand the water quality and prevalence of these household wells, 35 handâdug wells were surveyed and sampled near the HĂ´pital Albert Schweitzer in Deschapelles, Haiti. Water samples were collected and tested for fecal coliform and Escherichia coli using the IDEXX Colilertâ18 method. Of the samples collected, 89 percent were determined unsafe to use as a drinking water source based on the World Health Organization standard of 1.0 colonyâforming unit (cfu) E. coli per 100 mL. Sixtyâsix percent of the wells exceeded recreational/body contact standards for the state of Michigan (130 cfu/100 mL). Some of these wells were deemed suitable for conversion to a new well type called in situ filtration (ISF) wells. In situ filtration wells are installed with an internal sand filter pack, PVC casing, pump, and cap which seals the well from surface contamination and provides additional water treatment as water is pumped. Previous ISF installations have reduced E. coli to safe drinking water levels within 90 day
Geomorphic History of the Grand River and Grand River Valley: Natural and Anthropomorphic Hydraulic Controls
Preliminary investigation into the feasibility and benefits of removing 5 low head dams located on the Grand River, in the city of Grand Rapids, Michigan, is currently underway. The anthropomorphic hydraulic controls (dams), constructed in the late 1800âs, were built at the location of several bedrock exposures which served as natural hydraulic controls. Prior to dam construction, an abrupt change in river gradient at these exposures resulted in the rapids for which Grand Rapids is named. Evaluation of several alternatives for restoring more natural flow and sediment dynamics in the Grand Rapids reach is part of the removal effort.
This study provides a detailed explanation of the geomorphic setting and history of the entire Grand River, including new mapping and sediment data for five natural hydraulic controls that were identified during preliminary investigation of the region. These controls were confirmed through bathymetric mapping of a ~13 kilometer reach upstream of Grand Rapids between Ada and Lowell, Michigan. A 135 meter long and roughly 30 meter wide exposure of boulder-rich fluvial sediment was identified 5 kilometers upstream of Ada, Michigan. The exposure trends generally N-S and contains fine sand to large boulders. The surface of the exposure possesses a D50 of 87.6 mm and a D10 and D90 of and 12.2 mm and 1,302 mm, respectively. The subsurface of this deposit has a D50 of 14.8 mm and a D10 and D90 of 7.3 mm and 95.5 mm, respectively. The top of the deposit is not flat. Surveying indicates the elevation of the top of the deposit varies by up to a meter. This exposure provides unique substrate and habitat uncommon in the Grand River, which is primarily a sand and silt dominated river. Further mapping and sampling of this exposure may provide data which will allow this reach to be used as an analogue for restoration efforts in Grand Rapids.
The Grand River Valley (GRV), through which the lower Grand River flows, is significantly larger than the modern floodplain. Previous research has suggested that the GRV was formed, since the last glacial maximum (LGM), by glacial outwash travelling from the Huron Basin to Glacial Lake Chicago (in the Lake Michigan Basin). Mapping and analysis of approximately 40,000 water wells adjacent to the Grand River Valley revealed: 1) a bedrock channel, presumably occupied by the ancestral Grand River; 2) evidence for a Grand River outlet north of the modern location which predates the LGM; and 3) a N-S trending area of thick alluvium and boulder occurrence which may represent valley fill of the pre-LGM bedrock valley
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Geology, hydrothermal alteration, and geographic information system analysis of the Zortman Mine area, Montana
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Contrasting geomorphic responses to climatic, anthropogenic, and fluvial change across modern to millennial time scales, Clackamas River, Oregon
Geomorphic change along the lower Clackamas River is occurring at
a millennial scale due to climate change; a decadal scale as a result River
Mill Dam operation; and at an annual scale since 1996 due to a meander
cutoff. Channel response to these three mechanisms is incision.
Holocene strath terraces, inset into Pleistocene terraces, are broadly
synchronous with other terraces in the Pacific Northwest, suggesting a
regional aggradational event at the Pleistocene/Holocene boundary. A
maximum incision rate of 4.3 mm/year occurs where the river emerges from
the Western Cascade Mountains and decreases to 1.4 mm/year near the
river mouth. Tectonic uplift, bedrock erodibility, rapid base-level change
downstream, or a systematic decrease in Holocene sediment flux may be
contributing to the extremely rapid incision rates observed.
The River Island mining site experienced a meander cutoff during
flooding in 1996, resulting in channel length reduction of 1,100 meters as
the river began flowing through a series of gravel pits. Within two days of
the peak flow, 3.5 hectares of land and 105,500 m3 of gravel were eroded
from the river bank just above the cutoff location. Reach slope increased
from 0.0022 to approximately 0.0035 in the cutoff reach. The knick point
from the meander cutoff migrated 2,290 meters upstream between 1996 and
2003, resulting in increased bed load transport, incision of 1 to 2 meters, and
rapid water table lowering. Ninety-six percent of the total migration
distance occurred during the first winter following meander cutoff.
Hydrologic changes below River Mill Dam, completed in 1911, are
minimal but a set of dam-induced geomorphic changes, resulting from
sediment trapping behind the dam, have occurred. Degradation for 3 km
below the dam is reflected by regularly spaced bedrock pools with an
average spacing of 250 m, or approximately 3.6 channel widths.
Measurable downstream effects include: 1) surface grain-size increase; 2)
side channel area reduction; 3) gravel bar erosion and bedrock exposure; 4)
lowering of water surface elevations; and 5) channel narrowing. Between
1908 and 2000, water surface elevation dropped an average of 0.8 m for 17
km below the dam, presumably due to bed degradation
Physical Conditions in Circumstellar Gas surrounding SN 1987A 12 Years After Outburst
Two-dimensional spectra of Supernova 1987A were obtained on 1998 November
14-15 (4282 days after outburst) with the Space Telescope Imaging Spectrograph
(STIS) on board the Hubble Space Telescope (HST). The slit sampled portions of
the inner circumstellar ring at the east and west ansae as well as small
sections of both the northern and southern outer rings. The temperature and
density at these locations are estimated by nebular analysis of [N II], [O
III], and [S II] emission line ratios, and with time-dependent
photoionization/recombination models. The results from these two methods are
mutually consistent. The electron density in the inner ring is ~ 4000 cm-3 for
S II, with progressively lower densities for N II and O III. The electron
temperatures determined from [N II] and [O III] line ratios are ~11,000 K and
\~22,000 K, respectively. These results are consistent with evolutionary trends
in the circumstellar gas from similar measurements at earlier epochs. We find
that emission lines from the outer rings come from gas of lower density (n_e
\la 2000 cm-3) than that which emits the same line in the inner ring. The N/O
ratio appears to be the same in all three rings. Our results also suggest that
the CNO abundances in the northern outer ring are the same as in the inner
ring, contrary to earlier results of Panagia et al. (1996). Physical conditions
in the southern outer ring are less certain because of poorer signal-to-noise
data. The STIS spectra also reveal a weak Ha emission redshifted by ~100 km s-1
at p.a. 103\arcdeg that coincides with the recently discovered new regions that
are brightening (Lawrence et al. 2000). This indicates that the shock
interaction in the SE section of the inner ring commenced over a year before it
became apparent in HST images.Comment: 25 pages, 6 figures, to appear in December 1, 2000 Astrophysical
Journa
The evolution of ultraviolet emission lines from the circumstellar material surrounding SN 1987A
The presence of narrow high-temperature emission lines from nitrogen-rich gas
close to SN 1987A has been the principal observational constraint on the evolu-
tionary status of the supernova's progenitor. A new analysis of the complete
five-year set of low and high resolution IUE ultraviolet spectra of SN 1987A
(1987.2--1992.3) provide fluxes for the N V 1240, N IV] 1486, He II 1640, OIII]
1665, NIII] 1751, and CIII] 1908 lines with significantly reduced random and
systematic errors and reveals significant short-term fluctuations in the light
curves. The N V, N IV] and N III] lines turn on sequentially over 15 to 20 days
and show a progression from high to low ionization potential, implying an ioni-
zation gradient in the emitting region. The line emission turns on suddenly at
83+/-4 days after the explosion, as defined by N IV]. The N III] line reaches
peak luminosity at 399+/-15 days. A ring radius of (6.24+/-0.20)E{17} cm and
inclination of 41.0+/-3.9 is derived from these times, assuming a circular
ring. The probable role of resonant scattering in the N V light curve
introduces systematic errors that leads us to exclude this line from the timing
analysis. A new nebular analysis yields improved CNO abundance ratios
N/C=6.1+/-1.1 and N/O=1.7+/-0.5, confirming the nitrogen enrichment found in
our previous paper. From the late-time behavior of the light curves we find
that the emission origi- nates from progressively lower density gas. We
estimate the emitting mass near maximum (roughly 400 days) to be roughly
4.7E{-2} solar masses, assuming a filling factor of unity and an electron
density of 2.6E4 cm^{-3}. These results are discussed in the context of current
models for the emission and hydrodynamics of the ring.Comment: 38 pages, AASTeX v.4.0, 13 Postscript figures; ApJ, in pres
The impact of Participatory Budgeting on health and wellbeing:A scoping review of evaluations
Background: Participatory budgeting (PB), citizens deliberating among themselves and with officials to decide how
to allocate funds for public goods, has been increasingly implemented across Europe and worldwide. While PB is
recommended as good practice by the World Bank and the United Nations, with potential to improve health and
wellbeing, it is unclear what evaluations have been conducted on the impact of PB on health and wellbeing.
Methods: For this scoping review, we searched 21 databases with no restrictions on publication date or language.
The search term âparticipatory budgetâ was used as the relevant global label for the intervention of interest. Studies
were included if they reported original analysis of health, social, political, or economic and budgetary outcomes of
PB. We examined the study design, analysis, outcomes and location of included articles. Findings are reported
narratively.
Results: From 1458 identified references, 37 studies were included. The majority of evaluations (n = 24) were of PB
in South America, seven were in Europe. Most evaluations were case studies (n = 23) conducting ethnography and
surveys, focussing on political outcomes such as participation in PB or impacts on political activities. All of the
quantitative observational studies analysing population level data, except one in Russia, were conducted in South
America.
Conclusion: Despite increasing interest in PB, evaluations applying robust methods to analyse health and
wellbeing outcomes are scarce, particularly beyond Brazil. Therefore, implementation of PB schemes should be
accompanied by rigorous qualitative and quantitative evaluation to identify impacts and the processes by which
they are realised
Radiation hydrodynamics of SN 1987A: I. Global analysis of the light curve for the first 4 months
The optical/UV light curves of SN 1987A are analyzed with the multi-energy
group radiation hydrodynamics code STELLA. The calculated monochromatic and
bolometric light curves are compared with observations shortly after shock
breakout, during the early plateau, through the broad second maximum, and
during the earliest phase of the radioactive tail. We have concentrated on a
progenitor model calculated by Nomoto & Hashimoto and Saio, Nomoto, & Kato,
which assumes that 14 solar masses of the stellar mass is ejected. Using this
model, we have updated constraints on the explosion energy and the extent of
mixing in the ejecta. In particular, we determine the most likely range of E/M
(explosion energy over ejecta mass) and R_0 (radius of the progenitor). In
general, our best models have energies in the range E = (1.1 +/- 0.3) x 10^{51}
ergs, and the agreement is better than in earlier, flux-limited diffusion
calculations for the same explosion energy. Our modeled B and V fluxes compare
well with observations, while the flux in U undershoots after about 10 days by
a factor of a few, presumably due to NLTE and line transfer effects. We also
compare our results with IUE observations, and a very good quantitative
agreement is found for the first days, and for one IUE band (2500-3000 A) as
long as for 3 months. We point out that the V flux estimated by McNaught &
Zoltowski should probably be revised to a lower value.Comment: 27 pages AASTeX v.4.0 + 35 postscript figures. ApJ, accepte
Using ArcMap, Google Earth, and Global Positioning Systems to Select and Locate Random Households in Rural Haiti
Background: A remote sensing technique was developed which combines a Geographic Information System (GIS); Google Earth, and Microsoft Excel to identify home locations for a random sample of households in rural Haiti. The method was used to select homes for ethnographic and water quality research in a region of rural Haiti located within 9 km of a local hospital and source of health education in Deschapelles, Haiti. The technique does not require access to governmental records or ground based surveys to collect household location data and can be performed in a rapid, cost-effective manner.
Methods: The random selection of households and the location of these households during field surveys were accomplished using GIS, Google Earth, Microsoft Excel, and handheld Garmin GPSmap 76CSx GPS units. Homes were identified and mapped in Google Earth, exported to ArcMap 10.0, and a random list of homes was generated using Microsoft Excel which was then loaded onto handheld GPS units for field location. The development and use of a remote sensing method was essential to the selection and location of random households.
Results: A total of 537 homes initially were mapped and a randomized subset of 96 was identified as potential survey locations. Over 96% of the homes mapped using Google Earth imagery were correctly identified as occupied dwellings. Only 3.6% of the occupants of mapped homes visited declined to be interviewed. 16.4% of the homes visited were not occupied at the time of the visit due to work away from the home or market days. A total of 55 households were located using this method during the 10 days of fieldwork in May and June of 2012.
Conclusions: The method used to generate and field locate random homes for surveys and water sampling was an effective means of selecting random households in a rural environment lacking geolocation infrastructure. The success rate for locating households using a handheld GPS was excellent and only rarely was local knowledge required to identify and locate households. This method provides an important technique that can be applied to other developing countries where a randomized study design is needed but infrastructure is lacking to implement more traditional participant selection methods
An Assessment of Long-term Biosand Filter use and Sustainability in the Artibonite Valley near Deschapelles, Haiti
A non-randomized assessment of long-term biosand filter (BSF) use and sustainability in the Artibonite Valley near Deschapelles, Haiti was conducted during March, 2011. Of the 55 BSFs visited, 47% were no longer in use. Filter lifespan ranged from \u3c1 year to systems still in use after 12 years. Interviews with BSF owners revealed problems related to intermittent filter use due to travel for employment or personal matters; broken or missing filter parts; and fears that the filter would not be effective against cholera. In addition, 17 BSF field studies were reviewed to identify common issues impacting usage. Culturally appropriate technologies and education materials explaining proper maintenance and operation are essential for improved filter performance and sustainability. For Haiti, education materials should be provided in Creole and French and should include, (1) diagrams and descriptions of how the BSF works, (2) how to troubleshoot common problems, (3) how to properly maintain filters, and (4) a contact in case of questions. Operational problems can be minimized by providing long-term technical support, periodic water quality monitoring, and maintenance assistance for filter users