GIS For Biologists: Tip #16 – The ‘Shapefile Approach’ Vs The ‘Geodatabase Approach’ to GIS


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More St Venant Equations in #SWMM5

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This blog shows the relationship between the terms dq1, dq2, dq3 and dq4 in the SWMM5 code and the St. Venant Partial Differential Equations. dq2 = Time Step * Area wtd * (Head Downstream – Head Upstream) / Link Length or dq2 = Time Step * Area wtd * (HGL) / Link Length Qnew = (Qold – dq2 + dq3 + dq4) / ( 1 + dq1) when the force main is full dq3 and dq4 are zero and Qnew = (Qold – dq2) / ( 1 + dq1) The dq4 term in dynamic.c uses the area upstream (a1) and area downstream (a2), the midpoint velocity, the sigma factor (a function of the link Froude number), the link length and the time step or dq4 = Time Step * Velocity * Velocity * (a2 – a1) / Link Length * Sigma the dq3 term in dynamic.c uses the current midpoint area (a function of the midpoint depth), the sigma factor and the midpoint velocity dq3 = 2 * Velocity * ( Amid(current iteration) – Amid (last time step) * Sigma dq1 = Time Step * RoughFactor / Rwtd^1.333 * |Velocity| The weighted area (Awtd) is used in the dq2 term of the St...
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Vacuum Sewers

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Vacuum Sewers Compiled by: Beat Stauffer (seecon international gmbh) Source:   http://www.sswm.info/category/implementation-tools/wastewater-collection/hardware/sewers/vacuum-sewers Executive Summary Vacuum sewerage systems consist of a vacuum station, where the vacuum is generated, the vacuum pipeline system, collection chambers with collection tanks and interface valve units. In contrast to conventional gravity sewerage systems with intermediate pumping stations, the permanent pressure within the vacuum system is maintained below atmospheric pressure. Moreover, vacuum technology reduces water consumption considerably, enabling flexible installations regardless of topography and water availability. In addition, it allows for the use of alternative wastewater handling (blackwater and greywater separation). In Out Blackwater ,  Faecal Sludge ,  Greywater , Brownwater ,  Urine  or  Yellowwater ,  Faeces , Excreta ,  Energy Blackwater ,  Non-bi...
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