 Periodic flooding of the Canning River from the dam is required to disperse seed , stimulate germination and ensure seedlings survive , recharge shallow groundwater tables that are important during periods of drought and to discourage and prevent weed growth . However , during times of low rainfall periodic flooding is reduced . 
 Periodic flooding of the Canning River from the dam is required to disperse seed , stimulate germination and ensure seedlings survive , recharge shallow groundwater tables <a href='null_relcl' title='1'><mark>that</mark></a><a href='drop_aux' title='2'><mark>are</mark></a>important during periods of drought and to discourage and prevent weed growth . However , during times of low rainfall periodic flooding is reduced . 
Periodic flooding of da Canning River from the dam is required to disperse seed , stimulate germination and ensure seedlings survive , recharge shallow groundwater tables important during periods of drought and to discourage and prevent weeed growth . However , durin times of low rainfall periodic flooding is reduced .