Open Access

In this paper typical bypass efficiencies of sediment bypass tunnels (SBTs) used to counter reservoir sedimentation are described, distinguishing between two layouts of the tunnel intake. It results that SBTs are an effective measure to reduce the sedimentation of dam reservoirs, particularly of type (A) with intake at the reservoir head. The hydroabrasive wear of tunnel inverts is significant and has to be mitigated by using adequate invert liners. The invert abrasion can be estimated based on an abrasion model where a correct input value of the bed material resistance coefficient is paramount to limit model uncertainties. Based on abrasion measurements at prototype SBTs typical values of the material resistance coefficient are recommended for high-strength concrete, natural stones and steel liners. The field experiences gathered so far and the comparison of various invert materials suggest granite pavers as a promising lining material for severe abrasion conditions.

Abstract This study extends previous research evaluating the association between the CHIP intervention, change in body weight, and change in psychological health. A randomized controlled health intervention study lasting 4 wk. was used with 348 participants from metropolitan Rockford, Illinois; ages ranged from 24 to 81 yr. Participants were assessed at baseline, 6 wk., and 6 mo. The Beck Depression Inventory (BDI) and three selected psychosocial measures from the SF-36 Health Survey were used. Significantly greater decreases in Body Mass Index (BMI) occurred after 6 wk. and 6 mo. follow-up for the intervention group compared with the control group, with greater decreases for participants in the overweight and obese categories. Significantly greater improvements were observed in BDI scores, role-emotional and social functioning, and mental health throughout follow-up for the intervention group. The greater the decrease in BMI through 6 wk., the better the chance of improved BDI score, role-emotional score, social functioning score, and mental health score, with odds ratios of 1.3 to 1.9. Similar results occurred through 6 mo., except the mental health variable became nonsignificant. These results indicate that the CHIP intervention significantly improved psychological health for at least six months afterwards, in part through its influence on lowering BMI.