No abstract

No abstract

No abstract

No abstract

For the analysis of rainwater tank outcomes, some researchers used monthly water balance model, which ignores an important factor such as overflow from the tank. Recently, to improve the accuracy of such analysis facilitated by the availability of daily rainfall data, many researchers started using daily timestep models. In the daily timestep models, the daily rainwater demand is deducted from the available storage, once in a day and there are debates on whether to apply that deduction at the beginning of the day or at the end of the day. Moreover, there is significant diurnal variation of water demand, which can not be accounted for in a daily timestep model. To overcome this, current study investigates an hourly timestep model considering hourly rainfall data and hourly variable rainwater demands. Hourly rainfall data was collected from the Australian Bureau of Meteorology for a raingauge station located in Melbourne. An earlier developed daily water balance model was converted to hourly scale incorporating hourly variable rainwater demands. Model simulated results for three distinct years (dry, average and wet) were compared with the results using a daily timestep model with the same data. Variations of water savings and overflow amounts are presented under four combinations of roof area and daily rainwater demand with tank sizes varying from 2500 L to 20,000 L. It is found that in all the selected years, the daily timestep model underestimated the annual water savings compared to the hourly timestep model and the highest difference was estimated to be 13,750 L for a smaller tank size connected with a bigger roof having higher rainwater demand.

RESUMO Em razão do custo elevado de implantação das redes de distribuição de água em relação ao sistema de abastecimento, estudos referentes ao que influencia esse custo tornam-se essenciais. Parte significativa dele refere-se à complexidade na espacialização da rede e nas formas de ocupação territorial das áreas urbanas. No presente trabalho, os custos de implantação das redes de abastecimento de água dos setores urbanos com predominância de construções verticais são comparados com os de construções horizontais. Para o dimensionamento das redes, em concordância com as condições de vazão e pressão necessárias, utilizou-se o modelo computacional The Environmental Protection Agency Network (EPANET). Os custos foram baseados no Sistema Nacional de Pesquisa de Custos e Índices da Construção Civil. Observou-se que a rede implantada em áreas urbanas verticais apresentou custo 13,4% superior ao da mesma área com construções horizontais, mas ao mesmo tempo abastece um número de habitantes 13 vezes superior ao das áreas horizontais.

The traditional planting system still consists in intensive use of pesticides in Brazil. In the case of the municipality of Bueno Brandão, southern Minas Gerais, Brazil, there is a high concentration of potato crops. Some of the physical characteristics of the area are important for the subject since it´s plenty of springs and watercourses and very steep and rich in hills slopes that may offer risks to water quality by pesticide runoff. The cultivation sites are often located near slopes greater than 20 % in permanent preservation areas (APP/PPA) or near these. The most common APPs in the region refer to 30m wide areas along the river banks and 50m around the springs The Antas River is the main water source for Bueno Brandão and its contamination would be very detrimental to the health to both rural and urban population. Water contamination can occur due to sediment transport along the slopes toward rivers and springs that are found degraded riparian areas, causing water quality loss. One alternative that reduces the incidence of this problem would be the systematic application of Federal Law 12.651/2012 and banning any use of pesticides in plantations near the water bodies, preventing their degradation. As an additional measure the riparian forests should be recovered along rivers and around springs. Nowadays there are degraded forestal areas and open spaces. So even when crop _ields are out of APPs if the scenario presents potentially steep slopes there is still risk of sediment transport towards rivers. This study presents a macro view and a micro view to guide the recovery of gaps in the riparian zone and make it more feasible. The Macro view is a methodology to select priority areas more apt to promote the protection of the waters that may be vulnerable to degradation, and therefore more quali_ied to ecological restoration. Aiming at the resolution of the macro view, different physical characteristics and agricultural uses were correlated and some values were assigned to the associated impacts of each occurrence. Seeking resolution of the micro issues a survey was conducted on techniques and methodologies within Brazilian and foreign literature aiming at ecological rehabilitation and the regain of ecological functions that had been altered. These methods and techniques may be used at the discretion of the executors responsible jointly or separately depending on the project budget and the peculiarities of the chosen area.

First, this paper presents a thorough review of water quality data using a rainwater tank, categorizing the data as with and without sedimentation. Data are presented showing minimum, maximum, and mean values for the different parameters. The data measured from several sources reveal that water collected from the tank is much better than the water directly collected from the roof. In addition, to analyse the phenomena through a mathematical model, a hypothetical 5 kL rainwater tank with a 200 m2 roof was modelled with the MUSIC model. The simulations were compared with the measured water quality data from a rainwater tank in Melbourne. In general, we found that MUSIC’s simulations on the mean daily concentrations of total suspended solids (TSS) and total phosphorus (TP) are slight underestimations compared to the measured data from Melbourne. Further MUSIC simulations reveal that significant reductions in the daily maximum concentrations of TSS, TP, and total nitrogen (TN) are expected through a rainwater tank.