ON DELETE CASCADE

I'm trying to comb through my database and add ON DELETE CASCADE to a
number of tables where I already have fkeys in place, but I'm having a
hard time.

ALTER TABLE project_task DROP CONSTRAINT
"project_task_group_project_id_f" RESTRICT;

ERROR: ALTER TABLE / DROP CONSTRAINT: project_task_group_project_id_f
does not exist

ALTER TABLE project_task
ADD CONSTRAINT projecttask_groupprojectid_fk
FOREIGN KEY (group_project_id)
REFERENCES project_group_list(group_project_id) ON DELETE CASCADE;
NOTICE: ALTER TABLE will create implicit trigger(s) for FOREIGN KEY
check(s)
ALTER

That command works, but now I think I have 2x as many triggers as I
want. How do I get rid of the original triggers?

alexandria=# \d project_task
Table "project_task"
Column | Type | Modifiers
------------------+------------------+-----------------------
project_task_id | integer | not null default
nextval('project_task_pk_seq'::text)
group_project_id | integer | not null default '0'
summary | text | not null default ''
details | text | not null default ''
percent_complete | integer | not null default '0'
priority | integer | not null default '0'
hours | double precision | not null default '0.00'
start_date | integer | not null default '0'
end_date | integer | not null default '0'
created_by | integer | not null default '0'
status_id | integer | not null default '0'
Indexes: projecttask_projid_status
Primary key: project_task_pkey
Triggers: RI_ConstraintTrigger_51030049,
RI_ConstraintTrigger_51030047,
RI_ConstraintTrigger_4305858,
RI_ConstraintTrigger_4305852,
RI_ConstraintTrigger_4305846

After adding the new foreign key:

Triggers: RI_ConstraintTrigger_51364957, ***new
RI_ConstraintTrigger_51030049,
RI_ConstraintTrigger_51030047,
RI_ConstraintTrigger_4305858,
RI_ConstraintTrigger_4305852,
RI_ConstraintTrigger_4305846