Algae cultivation systems and methods adapted for weather variations

An open raceway algae cultivation system comprising:

• a channel including a high section and low liquid collection section, the channel sloped to allow substantially all of an algae cultivation fluid in the high section to flow downwardly into the low liquid collection section;
• a gutter defined in the high section;
• and
• a drain fluidly coupled to the gutter such that when substantially all of the algae cultivation fluid has flown into the low liquid collection section, any rainwater that falls in the high section will flow downwardly through the gutter into the drain, without the rainwater mixing with the algae cultivation fluid in the low liquid collection section.

A method of removing rainwater from an open raceway algae cultivation system, the method comprising:

• (i) circulating an algae cultivation fluid through a sloped channel;
• (ii) stopping the circulation of the algae cultivation fluid through the sloped channel;
• (iii) after (ii), allowing substantially all of the algae cultivation fluid in the sloped channel to flow from a high section of the sloped channel to a low liquid collection section of the sloped channel;
• (iv) after (iii), positioning a removable barrier in the high section of the channel;
• and
• (v) allowing rainwater that falls in the high section of the channel to flow (a) towards the removable barrier and (b) into a drain positioned in the high section of the sloped channel.

A method of removing rainwater from an open raceway algae cultivation system, the method comprising:

• (i) circulating an algae cultivation fluid through a sloped channel;
• (ii) stopping circulation of the algae cultivation fluid;
• (iii) after (ii), allowing substantially all of the algae cultivation fluid in the sloped channel to flow from a high section of the sloped channel to a low liquid collection section of the channel;
• and
• (iv) after (iii), allowing rainwater that falls in the high section of the sloped channel to flow (a) into a gutter defined in the high section of the sloped channel and (b) into a drain fluidly coupled to the gutter.

A method of controlling temperature in an open raceway algae cultivation system comprising:

• circulating an algae cultivation fluid in a channel having a first area and a first depth;
• positioning a removable barrier in the channel to confine the algae cultivation fluid to a second area and a second depth, the second area smaller than the first area and the second depth greater than the first depth;
• and
• removing the removable barrier to enable the algae cultivation fluid to fill the channel having the first area and the first depth.