text: create table water.billing_volumes (
    billing_volume_id uuid primary key default public.gen_random_uuid(),
    charge_element_id uuid not null
      constraint billing_volumes_charge_element_id_fkey
      references water.charge_elements (charge_element_id),
    financial_year smallint not null,
    is_summer boolean not null,
    calculated_volume numeric,
    two_part_tariff_error boolean not null default false,
    two_part_tariff_status integer,
    two_part_tariff_review jsonb,
    is_approved boolean not null default false,
    constraint uniq_charge_element_id_financial_year unique (charge_element_id, financial_year)
  );
  
  alter table water.billing_transactions
    drop column calculated_volume,
    drop column two_part_tariff_error,
    drop column two_part_tariff_status,
    drop column two_part_tariff_review;
  