Mass Balance Error?Mass Balance Error?https://oss.deltares.nl/c/message_boards/find_thread?p_l_id=1806765&threadId=4240602020-09-24T11:25:12Z2020-09-24T11:25:12ZMass Balance Error?Gyan Basyalhttps://oss.deltares.nl/c/message_boards/find_message?p_l_id=1806765&messageId=4240592014-05-08T16:13:08Z2014-05-08T16:07:24ZHello everyone,<br /><br />I have been comparing net volume of sediment deposited in a closed reservoir to total volume of input sediment but they don't match up. <br /><br />In order to calculate the former, I use cum. erosion/sedimentation data. Each data point multiplied by grid area (say 50 m by 50 m) gives net eroded or deposited volume at a point. Summing up positive values gives deposited volume and summing up negative values gives eroded volume. Adding them both gives net deposited volume assuming that you have sediment entering in to the system. Solid volume of the bed is then calculated by multiplying bulk bed volume with dry density of the sediment. <br /><br />I am using a morphological factor, so I multiply input sediment with this factor to calculate total sediment inputted into the system during the period assuming eventually all sediment will deposit (which is true in my model). Comparing the solid volume of sediment in bed to inputted sediment, I find the former is 65-90 % of the latter. There is indeed some sediment in suspension not accounted for in the bed volume calculation but I don't think it should make such significant difference.<br /><br />Is there anything wrong did I do in this comparison, or is it something you have experienced too? I would like to add that I have this issue when I have "sand" in the system. I have checked that the sediment isn't escaping the system and also tried smaller value of morphological factor. Introducing clay into the system, however, the comparison has matched up well. I am using default Van Rijn formulation for sediment transport and 3246 tag version.<br /><br />Thanks,<br />GyanGyan Basyal2014-05-08T16:07:24Z