Table schema:
CREATE TABLE table_26609958_1 (rainfall_totals__million_m_3__ VARCHAR, hydrographic_basin VARCHAR)

Question: When martha brae, river is the hydrographic basin what is the rainfall totals (million m 3)?
SQL: SELECT rainfall_totals__million_m_3__ FROM table_26609958_1 WHERE hydrographic_basin = "Martha Brae, River"