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Embankment dams are mainly made of erodible and pervious materials and are at risk from overtopping and piping, the erosion process that initiates may ultimately lead to the dam breaching. Estimating the flood and mapping the downstream area of the dam is essential to minimize the risk in the future due to the dam’s collapse. This flood calculation requires understanding the breaching mechanism and breach opening parameters. In Norway, earthfill dams are protected by placed ripraps on the upstream, downstream, and crest. Thus, this thesis aims at adding some information to the understanding of the breaching mechanism and process, examining the breaching parameters, and calculating outflow peak discharge during the breaching. In this thesis, experiments were carried out on a scale of 1:10 on dam models with placed riprap, single-layer dumped riprap, and double-layer dumped riprap each. Through experimentation and later analysis of these experiments, it is found that both placed and dumped riprap failure starts from just downstream edge of the crest in overtopping during breaching. Breach parameters calculated from available empirical relations significantly differ from the data obtained from the experiment. The data plot revealed that we could relate inflow breach discharge and outflow peak discharge with a linear equation. During the PIV analysis, it was observed that the failure between two dumped riprap was similar while observation with placed riprap was different. Through PIV analysis, it was also found that the breach in placed riprap occurs abruptly, and failure in both dumped and placed riprap starts just downstream section of the dam.

BACKGROUND: Undifferentiated febrile illness (UFI) includes typhoid and typhus fevers and generally designates fever without any localizing signs. UFI is a great therapeutic challenge in countries like Nepal because of the lack of available point-of-care, rapid diagnostic tests. Often patients are empirically treated as presumed enteric fever. Due to the development of high-level resistance to traditionally used fluoroquinolones against enteric fever, azithromycin is now commonly used to treat enteric fever/UFI. The re-emergence of susceptibility of Salmonella typhi to co-trimoxazole makes it a promising oral treatment for UFIs in general. We present a protocol of a randomized controlled trial of azithromycin versus co-trimoxazole for the treatment of UFI. METHODS/DESIGN: This is a parallel-group, double-blind, 1:1, randomized controlled trial of co-trimoxazole versus azithromycin for the treatment of UFI in Nepal. Participants will be patients aged 2 to 65 years, presenting with fever without clear focus for at least 4 days, complying with other study criteria and willing to provide written informed consent. Patients will be randomized either to azithromycin 20 mg/kg/day (maximum 1000 mg/day) in a single daily dose and an identical placebo or co-trimoxazole 60 mg/kg/day (maximum 3000 mg/day) in two divided doses for 7 days. Patients will be followed up with twice-daily telephone calls for 7 days or for at least 48 h after they become afebrile, whichever is later; by home visits on days 2 and 4 of treatment; and by hospital visits on days 7, 14, 28 and 63. The endpoints will be fever clearance time, treatment failure, time to treatment failure, and adverse events. The estimated sample size is 330. The primary analysis population will be all the randomized population and subanalysis will be repeated on patients with blood culture-confirmed enteric fever and culture-negative patients. DISCUSSION: Both azithromycin and co-trimoxazole are available in Nepal and are extensively used in the treatment of UFI. Therefore, it is important to know the better orally administered antimicrobial to treat enteric fever and other UFIs especially against the background of fluoroquinolone-resistant enteric fever. TRIAL REGISTRATION: ClinicalTrials.gov, ID: NCT02773407 . Registered on 5 May 2016.