How to configure ECMP for two static routes on DGS‑3630?

[Topology]
NetA / GW1 <-------(eth1/0/1DGS-3630 (eth1/0/5<-----Clients
NetA
 / GW2 <-------(eth1/0/3)

#NetA: 11.90.90.0/24
#GW1: IP 10.90.90.1/24
#GW2: IP 10.90.90.2/24

[Target]
Clients can go to NetA through GW1 and GW2 at the same time by the load-balancing.

[Config]
ip route 11.90.90.0 255.255.255.0 10.90.90.1 weight 1
ip route 11.90.90.0 255.255.255.0 10.90.90.2 weight 1

[Result]
1) Routing table:
Switch#sh ip route
Code: C - connected, S - static, R - RIP, B - BGP, I - IS-IS, O - OSPF,
      IA - OSPF inter area,
      N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2,
      E1 - OSPF external type 1, E2 - OSPF external type 2,
      * - candidate default
Gateway of last resort is not set

S    11.90.90.0/24 [60/1] via 10.90.90.1, vlan1
S    11.90.90.0/24 [60/1] via 10.90.90.2, vlan1

C    10.0.0.0/8 is directly connected, vlan1
Total Entries: 3

2) Traffic rate:
Port          InOctets /             InMcastPkts /
              InUcastPkts            InBcastPkts
------------- ---------------------- ----------------------
 eth1/0/5      8282432                 0                    
                     129413                   0                    

Port          OutOctets /            OutMcastPkts /
              OutUcastPkts           OutBcastPkts
------------- ---------------------- ----------------------
eth1/0/1      2898880                 0                    
                    45295                      0                    
eth1/0/3      5383552                 0                    
                    84118                      0 

Rank: 1.5