Constructed ponds and wetlands are widely used in urban design to serve a number of functions including stormwater management. The design of constructed wetlands for stormwater management involves a number of multi-disciplinary inputs. Fundamental to their sustainable operation are the proper control of the hydrologic regime of the wetland and optimal flow hydrodynamics within the wetland. Many ofthe problems encountered in constructed wetlands can be minimised or avoided by good engineering design principles. Poor wetland hydrodynamics are often identified as a major contributor to wetland management problems. Ponds and wetlands with a high hydraulic efficiency are expected to promote full utilisation ofthe available detention storage and near plug flow conditions. The shape and layout of urban ponds and wetlands are often varied to suit the landscape and to satisfy aesthetic requirements as an urban water feature. These can be achieved while maintaining an effective stormwater treatment outcome if steps are taken to ensure that the hydrodynamic behaviour of the system is not severely compromised. A consistent measure is required to allow the effects of design features to be evaluated against this criterion. This paper introduces a new measure for hydraulic efficiency that combines existing measures of flow uniformity and effective volume. Case studies are presented on the use of this measure to assess the effects of different pond and wetland shapes, locations of inlet and outlet, botanical layouts and basin morphology on the flow hydrodynamics.

This study analyses how the hydraulic performance diers between 13 ponds with hypothetically dierent layouts. The paper also includes a discussion of short-circuiting, hydraulic eciency and suitable parameters for measuring hydraulic performance. The ponds were studied by using a 2-D vertically integrated numerical model. Tracer studies were simulated and then evaluated and compared. The results con®rm that length-to-width ratio, location of in-and outlets, and subsurface berm have a large impact on pond hydraulic performance. There is also an indication that an island placed in front of the inlet improves the hydraulic performance, and that a curved pond or an island placed near the side does not decrease the performance. Ó

During the 1990s there has been a growing interest in (re)constructed wetlands and ponds for treatment of agricultural runoff, sewage water, and stormwater. Some of these facilities, however, are poorly designed in terms of hydrological and hydraulic performance, which strongly affects their treatment capacity. This paper gives an overview of the present knowledge regarding pond hydraulics in terms of effective volume ratio and dispersion. The importance of these parameters is demonstrated by modelling of nitrogen removal in 13 ponds of different design. The results show that effective volume ratio has a clear influence, which increases when removal rate coefficients increase, while dispersion is of minor importance for removal efficiency. Finally, the concept of hydraulic efficiency is discussed in the light of these results.

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The Visual Analogue Scale for Irritable Bowel Syndrome (VAS-IBS), a self-rating questionnaire, was designed to measure symptoms and the effect of treatment in patients suffering from irritable bowel syndrome. The aim of this descriptive correlational study was to conduct further psychometric validation after the VAS-IBS had been used in clinical practice, translate it into English, and compare the results with controls. Forty-nine patients with irritable bowel syndrome (median age = 38 years old [range, 18-69 years]) were compared with 90 healthy persons (median age = 44 years old [range, 21-77 years]) who served as controls. The patients with irritable bowel syndrome completed 3 questionnaires: the VAS-IBS, the Gastrointestinal Symptom Rating Scale, and the Perception of Change of Symptoms. Controls completed only the VAS-IBS. Results showed that the VAS-IBS is a valid questionnaire that measures the degree of change of symptoms and discriminates between patients who have irritable bowel syndrome from those who do not. It is important to compare the VAS-IBS among different cultural populations so we suggest that the English version of the VAS-IBS should now be used in English-speaking countries and be further tested for validity and reliability with English-speaking patients.