I have a large regional variable saturated model that we are developing to evaluate effects of mine de-watering on springs and streams in a mountainous area. There is about 5000 feet of relief in the model surface and the model ranges from ~1500' to 6000' in depth. I have 30 layers in the model, and am having problems with stable flow to my transfer boundaries. For example when I run the model at steady state I show ~9.8 cfs being discharged to the transfer boundaries in one drainage, then when I put the exploration adit into the model (using seepage faces along the decline) the discharge to the transfer boundaries in the same drainage is `10 cfs. Although I can understand that there is numerical error and precision issues, it seems the model shouldn't be able to create more water when water is taken out of the model. I am currently testing different closure criteria for both the inner and outer loop, as well as testing L2, L1, and Max error solutions to find and acceptable error/precision. Does anyone have any other suggestions that I could try to eliminate/reduce this apparent error?
Thank you for your help - Greg
